from what i undestand vrays gi engine is quite different to all others.
the IR Map for the secondary GI doesnt make sense for some technical reason, as far as i understood it.
a good and effective mixture is IR +QMC or IR & Lightcache p.e.
the special quality in Vray comes through combining different gi methods ( like biased & unbiased p.e.). this gives very high realism near physical correctness at very good speed.
for some reason i see brammelos post alsway as last? some strange time trap?
my answer is before his question now;-)