A year ago when compact flash cards were $200/gb, personal storage devices appeared to be a savior for photographers that took a lot of photos. Unfortunately, the PSD (personal storage device) never solidified itself as a reliable alternative to packing pockets with expensive compact flash cards. They weren't that reliable; they were big and heavy and had slow transfer speeds. To top it all off, the battery life just... well... sucked. Who needs a 20 gb hard drive when you can only transfer 2gb per charge?
Fast-forward to today. Prices of CF cards have dropped, but megapixels have risen. So is a PSD now a viable solution for dumping your photos to while you're on the go?
After a lot of research, I decided on the Compactdrive PD70X (the successor to the PD7X). Comparisson
Compactdrive claims that the PD70X is able to transfer from card to hd at 16mb/s (that's a blazing 11.2mb/s faster than the PD7x). It has a faster AA charger, regulators, no exposed buttons, more transfer per charge, etc) Just looking at the specs, it is apparent that this new unit (and the PD7x for that matter) meets the demands of today's photographer. The unit can transfer a lot per charge and transfers are relatively fast.
Ordering was easy. Eastgear seems to be one of the only "US" (they're actually in Singapore) distributor of Compactdrives. I decided on the 40gb version since I probably won't be taking more than 40gb of photos on a single trip. 
The shipping is a bit pricey, but it's Fedex 1-3 day, which happened to get to me in one day. Will the unit live up to its claims??
The box arrived.. well, it arrived.
The box outer box was ripped, but inside it was well packaged. (I got the 4 free NiMh rechargeables too!)
Inside the box, you'll find the manual, AC/car chargers, data cable, case, and PD70X unit.
The PD70X looks pretty slick. It won't win any design awards, but the brushed gunmetal is very nice.
Flipping open the right side of the PD70X reveals everything you need to control it. The on/off switch, xD/MS/MS Pro/MMC/SD slot, CF slot, the control dial, usb plug, and an activity light. The inside of the lid cover has common error codes in case the PD70X will throw one up, which comes in handy in case you're not the type of person to carry a PSD manual in your pocket everywhere you go. The command dial is easy to use, you can spin it up/down or push it in.
The PD70X comes with a sweet nylon? case with a red L stripe
Eastgear ships their unit with Samsung 5200rpm drives.
As you can see, it isn't the smallest unit around. Opening it up reveals that it is pretty much the dimensions of a laptop hard drive with the width of an AA over it, which makes a lot of sense. In this case size is something you will sacrifice for convenience. Not having to deal with proprietary batteries may become a life saver down the line when you have to dump and you run low on power. Most photographers who use external flash guns will probably have a couple of AA's lying around as well.
Operation
Operation isn't as straight forward as I would like. I'm the type of person that won't look at the manual unless the controls on a unit are just plain unintuitive. Well, this unit requires that you look at the manual. Only having three "buttons" means that you're going to have to do some crazy stuff like standing on one leg while pressing a button down to do some stuff (kidding).
Turning the unit on is easy as flipping a switch. When you turn the unit on without a CF card or memory card in it, it begins to read how much free memory is left on the hard drive. This is a bit annoying because you won't be able to transfer memory until after it does this. The alternative is to inser the CF card into the unit before turning it on. After this, transfering is as easy as pressing the command dial down.
Transferring is speedy. When it is done transferring, you can switch cards and begin a second transfer ONLY if you do it within 30 seconds. This, in my mind, is horrible. The unit is so fast that you insert a card, turn it on, press the button and set the unit down. When you turn around to put a new card in the unit has already been done for over 30 seconds, so you can't do a quick swap and transfer. The only way around this is to turn the unit on/off and do a new transfer. This wasn't a big deal to me, but it is a bit annoying so I thought I would mention it.
The Manual
As I mentioned, reading the manual is necessary. Unfortunately, it isn't well written (although more well written than a Sigma manual...) I ran into a problem with formatting the hard drive and apparently the manual has TWO sections for formatting the hard drive. The second is at the end of the manual, so I totally overlooked it. (It involves making a file on a cf card, inserting it into the unit, turning it on while pressing down the dial and then scrolling down, up, then pressing down again 
)
Build
The construction is solid. One thing to note is that there doesn't seem to be any space between the HD and the rear cover. The rear is a sheet of aluminum? or some type of metal meaning that there isn't that much material to absorb impact. You probably don't want to drop this unit (although you'd be a fool to drop it anyway).
The size is pretty compact and can fit into a bag no problem.
Unit in ACTION!!
In the field, the unit will be used to dump cards to when I fill them up. I own two 1gb Sandisk Ultra II's, so after I fill one up, I will dump and then use the other one. You keep repeating this cycle until you fill up 40gb of pictures or you run out of batteries. 
Each card you transfer to the unit is placed into a new folder (Starting from 0000, then going to 0001, etc.)
When a transfer is done, a smiley face and check mark are shown if the transfer was successful. The amount of data transfered and number of files is on the display for verification purposes. This information will stay on the display until you turn the unit off or press the command dial within thirty seconds (which will allow you to dump another card)
If you happen to turn the unit off and want to verify that you transfered information, it becomes a little more difficult as the unit can only navigate one direction (starting from 0000 to 0001, etc) but nevertheless, if you're curious you can check it, although I would try to verify when the smiley face first comes up if possible. Scrolling to the 30th directory might be a pain.
All the same information is available when scrolling through the directories, except there is no smiley face.
Transfering the images to the computer, it's as simple as plugging the data cable into the computer and then into the unit and turning the unit on.
Windows XP had zero problems locating my unit and allocating a drive letter to it. An interesting aspect of the unit is that it will act as a very expensive card reader as well. If you have a compact flash card in the unit and you plug it in, it will assign two drive letters, one for the unit itself (the hd) and the other one for the card. Note: if you take the card out and put a new one in, it won't recognize it until you turn the unit on/off.
Transfering is as easy as drag/drop. You can view the images on the HD, you can erase folders, etc. Note: the unit does transfer images from the cards directly, meaning all folder architecture is maintained from the card to the unit
Tests
The first thing I wanted to test was the transfer speed from card to the unit. Compactdrive claims that the maximum transfer speed is 16mb/s. This is faster than my fastest CF card can transfer, so in this case the bottleneck seems to be the card.
Test #1 856mb - 1 gb Sandisk Ultra II - 105.2 sec 8.136mb/s
Test #2 856mb - 1 gb Sandisk Ultra II - 104.6 sec 8.184mb/s
Test #3 947mb - 1 gb Sandisk Ultra II - 115 sec 8.235mb/s
Test #4 245mb - 512 mb Lexar 16x - 45.6 sec 5.373mb/s
Test #5 429mb - 512 mb Lexar 16x - 79.6 sec 5.39mb/s
One thing to note about this test is that transfer speeds are very fast. The 856mb transfers had a lot of small jpg files and the 947mb had larger RAW files mixed with jpgs. The device seems to handle transferring larger files a lot faster than it transfers smaller jpg files, but not by much. For reference/comparison, this site recorded speeds of 3.88mb/s-4.8mb/s for the PD7x, so it is very apparent that the PD70x is a lot faster.
What about transfer from the PD70X to the computer? Aparently, the unit transfers from card to the HD
faster than it transfers from unit to the computer
I recorded times of 107.3 and 104 seconds for 856mb (two different hard drives). This comes out to 7.977mb/s and 8.231mb/s respectively.
How much can it transfer per charge?
For this test, I charged up a fresh set of Energizer 2300mAh batteries (which happened to win the Great Battery Shootout). The manual states several times that NiMh batteries will lose charge overtime, so to get a maximum amount of transfers, you should charge the batteries before you use it instead of the week before.
Transferring was a pain because of the fast transfer speeds. It took a lot of attention, but I managed to transfer 35gb before the unit seemed to bog down. On the 35th transfer, the unit corrupted a folder and I couldn't delete the folder. (this is why I tried to format the HD) I probably could've transferred more files if this problem didn't happen. I'm guessing I could fill up my 40gb unit before charge ran out, as I had it plugged in for quite a while before I got the Err. 20 or "Please replace the batteries"
Conclusion
Inititally, I wanted to buy the Nexto CF, but there are no US distributors. The little information that I got on the unit pretty much directed me towards their website where you can e-mail and order one. Research threw around a ballpark number of 180 dollars for just the unit. I e-mailed and never got a response. Supposedly, the Nexto CF is the fastest personal storage device on the market and has a firewire connection instead of USB2 like the PD70X.
My tests of the PD70X show that it is just as fast as the Nexto or maybe just a TAD slower. This site claims that the NextoCF can pull transfers at around 9mb/s which might just be CF card variation or maybe the unit is marginally faster than the PD70X.
Compared to units like the Epson P-2000, the PD70X proves itself quite a capable unit in terms of usability. The P-2000 boasts transfer speeds of 2.2-2.5mb/s with Ultra IIs. My test with the PD70X yielded results of over 8mb/s, which is nearly 6mb/s faster than the P-2000. Fhoude reports 13gb of transfer on one battery charge for the P-2000 versus my findings of over 35GB transfer per 4 AA's. You can buy extra batteries for the P-2000.. for 60-70 dollars a piece, but the PD70X uses AA's which are cheaper and easier to come by. 
The PD70X doesn't have a display, hell the small screen isn't even backlit (I wish it was). It doesn't have a file browser (you can verify the size of the directory and how many files, but not each file individually). You can't go through and delete folders. Hell, you can't do much except format the HD (with the use of a CF card and secret code inputs - up down up down a b a b start select anyone?) or transfer cards to the hd (which it is VERY good at), but it doesn't need to really do anything extraordinary. This is a no frills PSD and it is very good at what it does. It might not impress anyone on a forum, but the peppy transfer speeds get the job done and they get the job done very quickly and reliably. If you're looking for a PSD for a trip or just to dump files on, I highly recommend this unit.
Thanks for your recommendations, Phi.
how much was it? im thinking about getting one. i was about to get the pd7x until i read some reviews that it was built like a piece of shit, which was why it was discontinued.