Exactly what I was thinking...
I'm a Honda guy though, and since you're not getting an 06 that R6 isnt' in the picture. My F4i made me a believer in Honda above all others, Yamaha a second and then "the rest."
600RR is a sweet bike, much much more aggressive riding position than the F3. I had an F4i, my ridding buddy had an F3 and then a 600RR, so we both got to feel the changes first hand. I'd say there is an equally large increase in aggressiveness from the F3 to F4i as from F4i to 600RR, and power moderately increases with each, not huge really by any means. It's mostly riding position and the increase in quality feel through the years, but an F4i and 600RR are very different bikes, I'd say just ride them and decide. Hell, ride 'em all!