TF10 attempts a far more colored, exciting sound. I say "attempts" because it isn't always successful imo. But it's got exaggerated bass, sucked out mids, and tipped up highs compared to the BA4. The TF10 lover would say the BA4 sounds too sterile and cold. The lover of neutral sound would say the TF10 is a caricature of what real music should sound like.
Essentially, the two don't really compete for the same audience, if that makes any sense.
Thanks for the response, that makes perfect sense to me. While I have started to appreciate the TF10 signature a bit, I'm still not too crazy about it because it doesn't perform too well for most of my songs. I'm thinking the closet thing I have to neutral are my m-audio AV40 and I quite like the sound of that so I'm 95% certain that neutral is what I'm looking for. BA4 it is!