Dave
ATCs don't sound bright at all to my ear. It's just that many pop and rock records (a fair bit of what I listen to) are splashy (at best) and ragged/awful through the presence (not uncommon) to totally screwed up overall (sometimes). I prefer something with a gently falling treble response, which isn't ATC
To be clear, I prefer a specific type of inaccurate speaker, which isn't to suggest that anyone else should.