I've got a Thecus N7700Pro NAS at home. They seem to be priced lower than comparable offerings from Synology or Qnap. I was lucky to get mine used, so saved even more money. Not sure about their reliability, though. My box is 8 years old (I've had it for about 3), and one of the 2 gigabit ports failed last year.
But one thing I do have to say about it - it is very, very fast. I don't normally notice disk transfer speeds, especially over a network, but when I got this box and moved my stuff onto it, it was very noticeable. I'm currently running my drives in RAID5.
Just ran a benchmark and got these numbers: