Performance

I think it can be assumed that when you put a SATA drive onto a USB bus you will be see a notable performance decrease. However, I think it's also clear that you are doing so for the sake of convenience. The BlacX behaves as expected, and despite its hot-swapping convenience, it will be at the price of a lot of access speed. I ran a benchmark using the POSIX 'dd' utility, first on my active boot drive and an identical drive in the blacX dock:

BlacX

4000000+0 records in
4000000+0 records out
4096000000 bytes (4.1 GB) copied, 159.909 s, 25.6 MB/s

real    2m39.932s
user    0m0.684s
sys     0m15.537s

SATA Drive

4000000+0 records in
4000000+0 records out
4096000000 bytes (4.1 GB) copied, 61.2139 s, 66.9 MB/s

real    1m1.837s
user    0m0.580s
sys     0m18.461s

As you can see, the price of USB is not a small one. The dock caused a loss in about 40 MB/s of speed. But you weren't planning on running an OS off of the dock, were you? These write times are fine for writing almost any storage, as long as you're willing to wait a few extra minutes. It also beat those of my FireLite portable drive by a few MB/s (due to the lack of space I had on this drive, I was forced to use a smaller sample):

400000+0 records in
400000+0 records out
409600000 bytes (410 MB) copied, 21.7235 s, 18.9 MB/s

real    0m21.885s
user    0m0.064s
sys     0m1.616s

Conclusion

All in all, the BlacX has an intended purpose, and serves it very well. It can turn any SATA internal drive into instant portable storage, and saves the possible pain of installing and removing hard drives from a laptop or desktop machine. If you need to do lots of backups, or even don't have enough space in your machine for all of your drives, this dock is an excellent choice.

Pros:

• Ease of use (no drivers needed)
• USB 2.0 for fast transfers
• Works with 3.5" and 2.5" (laptop) drives
• Size is not intrusive

Cons:

• Speed loss
• Hard drive sticking up may be unattractive
• No FireWire or eSATA
• SATA Only