I agree with Derek (Sal), try more than one, but give it a chance. I've been using the 18 for about a year and a half. I definitely prefer it highway riding as well as around town riding solo. Sunday riding with my wife 2-up makes me miss the 17. With the 18, 5th is more like an overdrive. I don't usually use 5th below 60. It makes highway cruising of 75-80 a lot smoother.
Going up a tooth also makes the gears slightly taller where you would tend to stay in each gear a bit longer. The only negative of the 18 to me is that it cuts down on quick starts if you're heavy or riding 2-up. Also, I probably wouldn't like the 18 if my bike were stock. Less restrictive exhausts, no AI, re-jet, opened up airbox, UNI - all gave the bike a noticeable power increase. Without at least those changes, I'd probably stick to the 17.
I thought about going back to the 17 and may try it again, but I've gotten quite used to the 18 now. There's probably a reason that is what's stock on all the new models.
