No Honda fans in here huh? Guess not!
My .02. If you have ridden the later model r1 bikes (04+) and going to another liter bike, I would stay away from the zx10r. You will be guaranteed disappointed. If you are a lurker on the ninja sites like I am, you will see that these guys steal parts from other bikes all the time. Crappy brakes, weird design and some unreliable electronics. The only thing that the zx10 has on any other sport bike is comfort! I dd (daily drive/ride) on a motorcycle and borrowed a buddies zx and it is like a Cadillac (IMO)
R1 is a great bike. Love the power and handling but hate the comfort but I will take that bike to the track any day of the week.
K5 gixxer is a great all around bike, light weight, very nimble, average comfort for a sport bike. Good power and a ton of aftermarket support that's why a lot of people flock to it. Not gonna lie tho it's the ugliest of all sport bikes though.
I'm a Honda guy and I won't bore you with how great the 1000rr is (because it is, named best sport bike several years in a row... Oops lol) but none of these bikes hold their resale value as good as the cbr does. So also think about which would at least be a great investment. Gsxrs and zx do not hold their value because the market is flooded with gixxers and zx just can't sell like the others. I was at a dealership an saw an 08 zx selling got 4800. Pretty cheap for its generation. Find what you want to do with the bike and then make the decision
Sunday rider/bike tuner=gixxer
All of the above= 1000rr lol
Don't bite my head off guys. All just my opinion