Yes, the $299 Synology DS-410j. I have been thinking the same way. Despite that prices have fallen over the last year, I can't help but say that most other models seem overpriced.
I could certainly come up with 2x or 3x the money for a 4-bay NAS. I guess it could get me 2x or 3x the write speed. But not even 2x the read speed. The same UI. The same capacity. The same reliability.
AFAIK this $299 Synology DS-410j delivers 30MB/s write and 60MB/s read on RAID-5. It seems to me the next higher model, they're asking $600, $800. It just seems like extremely diminishing returns. OK I get hot swap but I'll probably use that once a year. Faster write speed is nice I guess, but most of my transfers are "start it and come back later" anyway, and actually I won't be doing many transfers if my torrents go onto a central server from the git' go. I only have 20 megabit down on my ADSL from newshosting.com.
I'd like to convince myself to spend more money, but I just can't figure it. It seems like the next model up is at least $500 or $600. I could buy TWO of the $299 Synology DS-410j and stuff my old 1TB drives in it after I move over to the first one. Am I missing something here folks?