fortus, but thats mainly due to the fact that he gets the shanny solos in the less rampaging songs so they are easier to play and more difficult to alter.
still, i like when any players deviates from the original so long as it still sounds good.
You said you think ron generally keeps it tightest, this is probably due to the fact that hes only been in the band a short time. Listen to early buckethead renditions (they effectively play the same bits), at first they were pretty close to the originals (obviosusly in a bucket style) by the end of the '02 they had evolved. The same will happen with ron.