Pretty much what Brent said, but I prefer belt instead of shaft drive. Not saying it's better or worse, just what I prefer. I have had fewer issues with belts wearing out or breaking due to debris than my shaft drive rs4 3evo. So it really isn't a durability issue, just personal preference. I'm hoping to get some serious speed with my latest gpx4, but like mentioned, am going to be stuck with 1/10 wheels. Thats a drawback for those seeking crazy speeds, but if I can get it into 80's-90's with 1/10 scale, I'll be more than happy. So, the answer is, shaft or belt is fine. Never had issues with them slipping off pulley or undue breakage or wear. But, when it comes time for a teardown for cleaning and maintaining, shaft drives are SO much easier to work on.