Hi there, I have been riding offroad bikes for a while now, and I decided that I wanted to ride onroad again, and like you was undecided on what to get. I was in the mindset to buy a CBR 1000RR, but when i went to look at both the bikes, i fell in love with the 600RR, it is lighter, more agile, excellent midrange, and easier to handle because of the weight factor. Speed wise the 1000 has more top end and the midrange in 6th gear is better, but unless you are planning to ride over 260kmh on a regular basis, then the 1000 in my opinion is only a better buy if you are a big/heavy person. Both bikes are awesome, but I bought a brand new CBR 600RR 2006, and I am not regreting it one bit.