bikes are no different than cars and stereo's etc....

your always going to want more speed, sound etc....

though the new style 600's are as good if not better than slightly older 750's they are not going to rip your arms off like a nice turbo hayabusa would.

when i first got my 600 i was suprised by the power, now i realize that its pretty much dogshit above 80mph and the engine is so low on torque that too little rpm on a start makes me have to clutch in some more power or it will not go

but if you have little or no experience on bikes any new 600 will be more than enough for ya