22-18 is real nice, on natural I prefer 22-19 though. You dont want to go to a 20 tooth chainring unless you have to clear a huge chainstay yoke or something (like the XTP). 20 tooth rings put more tension on the chain and snap them a little more frequently, unless youre pretty smooth. Anyway, that's my opinion and my experience.
I ran a 22-17 for a week and my pedal kick gap increased by 1 foot. THe problem was it was hard to maintain balance in such a hard gear. Im now running 22-19 which is quite a bit easier, but I think I'm going to try 22-18 when I get a new rear wheel.
I'm somewhat of a beginner (about a year of riding), and I've found that 22-19 gives you a big more torque on natural. You can overcome the chaotic features and get on your rear easier. I suck, so I'm on my ass most of the time.
22-18 or even 17 is a bit more fun for urban. So there ya go.
I agree, I'm kinda a begginer/sport after 4 months of riding, and from practicing on palets, I've found 22-17 a bit easier, but having a harder gear and being able to pedal kick farther is much more rewarding sometimes.
i started out on 22-15. learned to pedal gap and pedal up like a sun-ov-abitch. quickly learned that i was retarded for running that gear. ran 22-17 for a year. now ive been on 22-18 for about a year as well. i ride mostly urban.