Dude I love my DT 90s although sadly I think they are soon to be replaced by a HE 400 [linear sub bass from 30hrz and up and those orthos mid]
 
Still for the price [Dt 990 is about 1/3] of an HE 400, it is a MOST epic can... and for classical I enjoy the dt 990 the most <.< not even sure IF I'm going to sell my 990 or not honestly 

Ooh, I almost bought one a while back, from what I've read I'd say the Hifiman is quite different from the Beyer. The HE 300 and HE 500 both have got my #2 interest in headphones I want to hear, right after my HD580 after it's been refurbished. I'd stick with the DT990 though, they don't sell for even half their original price here and I think they're really different from all others in this price range