Thank you for the replies so far. I am interested in what people like or don't like about the various types.
To be honest, there is not a lot to them as far as daily interaction. You seldom have to do anything with/to the NAS. I have a 4 bay QNAP.
Thoughts:
1. Heed the warnings regarding buying more disk space than you think you need. Also note that you will want to run a RAID scheme, which can double the storage requirements depending on the RAID scheme chosen (ie: 2TB will be required to store 1TB + its mirrored backup copy).
2. Get a brand that provides regular updates. Both QNAP and Synology offer frequent firmware updates and OS patches. You still have to worry about viruses and such infecting the NAS. Frequent updates help with this. The same advise goes for modems.
3. I like that the QNAP has its own OS, CPU, RAM, etc. It runs on a linux OS internally, but interfaces with windows or macs seamlessly. It allows me to make full backups and disc copies from USB ports on the NAS itself, so no need to go over the network. When I first got it, I used it to run Kodi and JRiver directly from the NAS, without the need for another PC. It is also controlled the way Homer described... with a browser based UI. There are dozens of apps that can be loaded on it. Want to dump home surveillance video onto it? check. store videos and photos? check. You want a server you can access from a different location over the web? check. Apps galore are available. Mostly free.
4. Remember, the drives themselves do not come with the NAS. They are purchased separately. I ran my 4 bay with only two installed drives for quite some time. My NAS required all the drives be the same size (or you would be limited to the size of the smallest one in use). If you go with 2TB drives, the best you can do even without RAID is 8TB. But 6TB drives will give you 24TB, and the drives themselves only increase in price moderately in going from 2TB to 6TB. I couldn't start with 2TB drives and then add two additional 10TB drives at a later date hoping to get storage space beyond 8TB. I would still be stuck at that 2TB limitation. I'd be better off removing the two 2TB completely and using only the two new 10TB drives (20TB total storage vs 8TB) . Other NAS brands may not work this way, so YMMV
5. You will get various opinions on the different drive brands, but I've had the best luck over the years using Western Digital. Whenever I've had to replace a drive in a PC or laptop it always seemed to be a Seagate drive. I use four 6TB WD reds.