Hey Steven, You are right. Arnold is pretty much looked upon as the magical solution to everyone's rendering problems (i know because i certainly think it too when sh hits the fan with what i use), which tends to become annoying. But i'd love to see a displacement test of both. Unfortunately there's no trial version of arnold yet. What i'm thinking is maybe i could find someone on this list that has a similar proc as mine (i7 3770k 3.5 ghz), and we could share a similar scene with the same model and displacement map, just to get an idea of rendertimes and memory footprint at the same res.
If anyone is up for it, send me a mail. I have a couple of days to kill until the next gig.