Hey man, take the other dude's advice and sit on 'em both. Well, just sitting on them won't do much good but at least you'll get a feel for the riding position. And believe me, when you begin to ride a lot, the little differences amount to some huge results around twisties. A buddy of mine had a F4i and compared to the 600RR, the F4i lets you feel like you're more planted "in" the bike. I think it's because the bars are higher. The F4i actually feels a lot like gixxers (GSX-R). And according to my arse dyno, the F4i pulled a little weaker off the drive. It revs slower and lower. But it's much lighter and more comfortable. It felt slightly skinnier around the gas tank too, which in my opinion, is a good thing. I like the overall design of the RR but the F4i isn't a bad looking bike either. To be completely honest with you, I think if you get the F4i, you'll regret not getting the RR, but if you get the RR, and learn more about bikes and riding, you'll appreciate the F4i's too. To put it simply, the RR's are more sport-oriented and the F4i is a better street bike simply because of comfort. But that's not to say that the F4i is a slouch. It isn't at all. Blah blah, I'm writing too much so let me just lay down for you definitely. Get the RR, but do lose the stock exhaust system (you'll shave off a ton of weight), and make sure to get a fuel management system to smooth out your power.