The "reliable, affordable (and relatively cheap) bit bucket" has become the taper's Holy Grail, lol. If a manufacturer would make one in a Sony M-10/Edirol-Roland R-05/09 size with a normal SPDIF input, we'd have a winner. That said, the 661 and R-44 are likely your best bets for reliability and compatibility in the lower price range. I haven't had an issue linking the R-44 with with anything and I've heard the same anecdotes about the 661. Never used/owned a DR680, and they are getting cheaper, but I understand they're fairly compatible with a lot of preamps.