Edit…Result! You can ignore the rest of this.
I’ve got 2 x Qnaps; an old 209 and a new 269.
1) They aren’t cheap.
2) Qnap’s support isn’t great though the forums are! Check out the forums for their lamentable ability to fix some blaring holes in the linux build they use. Synology are much better at this.
3) They build in lots of little “features” in their linux build that stop you doing things though that’s only an issue if you want to start tweaking things outside the UI,
Having said all that, they are really simple, and they pack in lots of features (which you may or may not need). They’re basically mini web and applications servers.
RAID 1 – This will halve your available storage and will protect you if one of the disks goes bang in the NAS. If you look for a single disk NAS, this isn’t and issue (you need at least 2 drives). The chances are that if you have Data on a source PC that you then back up to the NAS, you might decide it’s OK to lose the NAS and still recover all your data from the PC. (It’s a choice, and usually down to budget).
The best thing you can do is take a snapshot of the NAS data and move it “offsite” In the event of something catastrophic like a fire you can’t rely on a NAS for “backup”. If it’s got all your family photos on use a portable drive or something similar and leave it somewhere. (not at the side of the road though :) ).