The Rocket puts out more heat than the water cooled Ultra, the only difference is that the Rocket stays together and the Ultra has to have a chase vehicle picking up parts falling, at 2 months old the Ultra had to have the clutch replaced, at my cost, the shocks replaced under warranty, the auxiliary lights repaired and the info center repaired,,,,,almost forgot, the shifter fell apart and i had to put it back together in the middle of nowhere and the tools they give you are as good as a pile of bricks because nothing fits that nut