I hate to be all Gustradamus on y'all, but I stand by my prediction that K will do well and Folau will be a flop. As much as we all laugh at the PDF and the tee-ball pedigree, Karmichael was more an athlete playing footy than a specialist footballer. I remember his first press conference as Test fullback, and how upset the media were that he knew nothing of RL history, and was more interested in basketball. But that tells the whole story. Rugby league is just something he sort of fell into. He could quite easily have gone the other way, and if he'd gone with AFL since high school he might already be an Aussie rules star.
Folau, on the other hand, owes all his success to his strength, vertical leap, and speed, and outside the rugby codes, I can't think of any sport in which he would excel.
One thing I'd love is to see (which will never happen) is for Karmichael to have a crack at the NBL. He'd make a great point guard, and I reckon the purple and gold of the Kings would look great on him.