They actually isolate a bit better than their wooden older brothers and don't leak too much sound unless you blast the music. Not the greatest isolation ability you can get from a portable can but definitely not the worst, either. Great as a street can, IMO.
As for SQ, I actually find them somewhat close to the HD25-1 II sound, with little more bass emphasis and more forward mids... I'd rank them the same in terms of overall fidelity when they're stock. Since the HD25 SP's are reportedly a bit inferior to the 1-II's in SQ, I'd say you'll get some improvement in overall SQ with ES7.