I'm looking into upgrading my very old crankset on a 2002 NRS and was wondering which of these would be best. I understand the weight penalty of the V-drive but if they last I don't really care and from the reviews on the Afterburner I'm being swayed that direction especially with the price difference. In all fairness most of the reviews refer to the non megaexo afterburners though. So can their price be justified? Main issues are longevity and performance. The only other contender are the Shimano XT's. Opinions?