I have a 1992 Yamaha Badger that is probably the most abused quad ever, and it still runs. 8 years without an air filter on the front snorkel and it still runs fine, never changed the oil but maybe once a year or two. It smokes like its a diesel but it still runs. Then my little sister got a 00 Honda TRX90 and it has been nothing but a pain. Everything is broke on it. The motor gave up after maybe a year and that is with proper care. The Badger was also faster and still is. My 400EX is also junk, everything has been replaced except the motor and that is still running strong. One thing I have learned is that Yamahas break down less than Hondas, Hondas are always little stuff, Yamahas run strong until something major happens, then you pay alot to get it fixed. Overall they are all pretty decent machines now a days.