East West stuff is very good, but very raw. I don't mean that as a criticism. I mean it is very good at replicating real life recordings of things like choirs. Their orchestra / choir stuff is designed for doing recordings without actually doing recordings.
If you want a choir sounding instrument then you might be better off with something mid range. If you think Nexus sounds good then you are in luck... Nexus is crap. Kontakt maybe? Native instruments do mid-range sample based orchestra / choir stuff. Better quality than something like Nexus but easier to use and more ready than the high-end stuff.