in my oppinion a 400 ex is an excellent beginners machine and is probally one of if not the most reliable of the 400's out there. i would also buy a good used machine if its your first quad. later on there is alot of updates you can do to a 400 ex to improve power ,perfomance, handling and such. like previously stated go with a water cooled and use engine ice in the cooling system and it should run pretty cool for riding long periods of time.