Sure SE115 or Beyerdynamic DTX100?

I'm looking for some headphones for listening in the office - noise isolating is definitely good! 

So I head over to the What Hi Fi headphone reviews and see 5* ratings for both the Sure SE115 and Beyerdynamic DTX100 at £100.  Online prices seem to favour the SE115 at ~£70 rather than the DTX100 at ~£85.  But unfortunately the reviews don't comment on the differences between the two.

Anyone like to suggest whether the DTX100 are worth the extra over the SE115?  Almost all my listening is classical.

Thanks in advance.