We focused on NASes that cost less than $350 (diskless). Setup should be simple, and it should come with good mobile apps for media streaming and remote access. It should have several USB ports, for backing up external drives to the NAS (and vice versa) as well as connecting printers or Wi-Fi dongles. It should also support hot-swapping-changing hard drives without turning off the NAS. Dual-drive NAS devices support drive mirroring-the contents of one drive are copied to the other, so your data is safe even if a hard drive fails.
