By Alaik 2010-01-05 16:25:45
One thing to be said, it obviously doesn't make a large difference on way or another, so it's probably considered wisest to act as if they are the same, and base your choice off of the other stats it gives. (Emissary beating Dance due to +parry also, etc, etc)
Personally, I think skill > eva on very high leveled mobs (83+) and eva > skill on everything else from my parse records, however, every legit parser shown so far all have the common result of the increase being marginal at best.