JVC HA-RX700 or RX900 for Metal

Hi there.

I finally decided on my new headphones (I hope :P)

As you can see from the title I listen to metal (mainly, but I also listen movies's sound tracks, some hip-hop and classic music one in a while).

Is there any difference between the two JVC that would suggest me to buy a pair instead of the other?

Thanks!

There's no need to reply to this thread. 

I made up my mind and I'm going for the JVC RX700. :)