Pros: 4 drive bays, compact

Cons: Contrary to the description, the drive bays are NOT hot-swappable, and this thing killed four known good hard drives before I realized what was going on.

Overall Review: The product description states that the 4 drive bays are hot-swappable, but as I learned the hard way, they are not. The first time I tried to hot-swap insert a hard drive (using a motherboard that supports hot-swap sata of course), the whole system powered off immediately, as if I had pulled the plug, and the hard drive was completely fried. The system would start up if the drive bay was empty, but would not power on with any drive (not just the fried hard drive) plugged in. Eventually I realized that if I plugged in another known good drive (while the system was off), that hard drive would also be immediately fried if I tried to power on the system (the lights would blink, but the system would not power up, and the hard drive would be fried). If I plugged a fried drive into another bay, that bay's power distribution board would immediately fry, and would also fry any further hard drives that were pugged in. I killed four known good hard drives before giving up on this piece of junk.

Pros: It didn't explode

Cons: Didn't work at all, twice DOA

Overall Review: The first drive was DOA. Wouldn't power on. I RMA'd it, and the replacement drive was also DOA. I tested my cabling and power source with other known good drives, and they all worked, so it's definitely the drive. I'll never buy another WD hard drive.