eton 90 all the way, My boys have both My 7 year old rides a tricked out 50 and my 12 year old ride the 90. My sons 50 with just a pipe, some clutch mods and a variator blows the doors off his brothers eton 90, Predator 90. I havent even put his airsal 70cc cylinder on yet Eton makes one of the most reliable kids quads, if not the MOST reliable quad on the market!!!!!!!!