I've never ridden a 1000, but I've owned two 600s and ridden a 750. To me, the 600s are very fast....faster than you would ever need. The 750 I rode had much more power and it was pretty noticeable. I'd imagine the 1000 would be the same way. If you have experience and know what you're doing, I'd say the 600 would be just fine. It's got more power than you'll ever use, unless maybe you plan to race it professionally on a track.