ive been running a set of um o6s for 4 years now, with 40s, and 37s, and now 36s. and lets just say i do some nasty things to this truck. i have a high hp 22re, dual ultimate cases, dual lockers.
if it can stand up to my goofy butt for 4 years, its a product to stand by. are the longs stronger?? ya, but not by a whole lot. not cost effective. if your doing things that will break an un-o6, youll break a long shortly after 
sweet that's what I was looking for.
After tax and shipping, they're close to the 27 spline longs in price but this is Marlin and they've given me awesome service with all my orders. Plus there's no grinding involved
