I really miss Foobar2000 on Linux (I've tried it a few times with Wine, and was never impressed vs. running it natively on Windows), so this looks like it might be just up my alley - especially since it has custom tag support.
Really? I noticed it's slower to start up but other than that it seems the same. I use it pretty regularly because foobar components handle formats the others can't.
Other than that, I'd say Audacious is the closest Linux analogue to foobar2000. My one big gripe was freezing up for a bit when a stream cuts out (blocking socket?) but they fixed that.