CR --
I'm not aware of any specific problems with the Buffalo products. That said, there may be some, but I wouldn't know of any. Perhaps Rolf can chime in, as he has significantly futzed with our routers here.
The Buffalo products are nice, in that configuration is totally web-based, and is really straightforward. (Though they do have plenty of scary packet-filtering and NAT options, that I don't go near..)
I've got one running at my parents place (they are tech illiterate), and it's had an uptime of >1 year. If only their windows installs worked so flawlessly....