I consider the same. Not sure what else i might get but i NEED really a choir. But it should be just one since i think i have already enough to learn and master with either of these.
Since i´m more into these ambient textures and huge but not in your face choir sounds i guess EWC might be the better choice? Especially since i already own HZS and it might sounds well together recorded in the same space.
I watched endless videos and it´s still hard to tell what will be better in a long term.
I think the kind of evo-grid and that i like the GUI in the Spitfire app much more (yes, i really prefer it over their Kontakt instruments) it will be the EWC. I just wished there was a more standard with less mic version as well.
However, both options seems as low as possible right now for a long time maybe.