Synology DS1019+

It might not be the cheapest, but 4+1 drives is more efficient than 3+1. Currently I have three 8TB drives: 1xWD Red and 2xIronwolfs (wolves?) with one running as parity (SHR). No complaints. It does everything I need it to do. The interface is simple and everything "just works" as anticipated. If/when I run out of space I plan on adding another 2x8TB drives, probably more ironwolves.

I wouldn't go bigger than 8TB as they already take DAYS to add to the array.