For single user home use this little guy rocks. It's slightly older tech, but my needs do not demand peak performance (Most scheduled tasks are afterhours anyways). I use this to back up a secondary volume in my desktop PC, so even though it is a 1 bay system I still have redundancy.
Cheap - I picked up mine for about $110; Versatile app selection and intuitive interface; OS seems very stable and snappy despite only having a single core 800 MHz proc and 256MB of RAM
3Gbps SATA2 connection; 6Gpbs SATA3 would have been nice, but it is an older model and very (relatively) cheap, this is an acceptable tradeoff for a single user environment; USB 2.0 instead of 3.0; Once again, acceptable tradeoff.