hmmm....i have an RC51 and a Niner, I love them both. the twin is AMAZINGLY smooth in the powerband, but as a daily rider, i definately prefer my niner. an I4 is smooth, never misses a beat, and i can use blue loctite instead of red or (yes, i've had to) green... that's the stuff that is never ever ever ever ever supposed to come off...it's sleeve retainer... anywho, the novelty of the thump thump sound wears off a bit, and the buzz starts to annoy a person a bit. but every time i ride my niner, i am happy!
30,000 mile 919 survivor. No plans of stopping the abuse any time soon.