One BIG problem with EW Symphonic Choirs is that the ranges are wrong for standard choral literature.
EWQLSC is a gorgeous library. I love it.
But you have to use it for what it can do, not what it can't do. Anyone who expects to do standard choral literature is going to be disappointed. This is human voice, and you're just not going to pull that off - in fact someone tried to do the Mozart Requiem with it a couple of years ago, and despite all the raving on Nothernsounds, it was a complete disaster in my opinion.
You have to treat sampled choirs as a different kind of instrument from real choir. They usually want to be doubled with other instruments, and you rarely want to use them exposed. Maybe VSL's choir will be different - and I hope that it's an advance over what's out now, otherwise what's the point? - but it's hard to imagine a sampled choir that doesn't have more limitations than capabilities.