ninja gets about 10+ mpg less, according to the estimates. i lvoe the CBRs too, want a 600 but no way i need that much paower, i'm 5'9" 135lbs soaking wet. i didn't want to get a used bike because i'm cautious with that kind of stuff, not knowing how many owners it's had, condition it's been kept in, secrets the seller is hiding...plan on keeping this bike for awhile, and i think i can convince the wife to take it over once i upgrade to my 600...i am just a CBR fan i guess...ninja looks more aggressive, but aside from 1 second faster from 0-60, the ninja doesn't impress me over the CBR.