For me, the proportion of children to adults is an overriding factor. It stands to reason that if you have two very large adult choirs, you need a larger number of children. Mahler had roughly 350 children for the world premiere - a number that I believe has not since been duplicated.
Regardless, I'm withholding judgement until the CD actually arrives. So far, the cast of soloists is a bit of a mixed bag (as it nearly always is). I find Barry Banks (tenor) tolerable, but not outstanding either. I do like the way they made the crappy Paiste tam-tams audible and 'ring on', without them also sounding like someone bashed in an over-sized cymbal.