I did about 35 miles today on my new Conti 240 rear tire.
I installed the wide wheel and Conti tire in a effort to get better traction on the street, where I was tired of constantly lighting up the stock tire in 1st through 3rd gear when jumping on the throttle. From my past experience I knew that the Metzler, Avon etc. would probably not be any better than stock, but when I saw the Continental Race Attack tire was introduced and researched it (and Oliver spoke highly of it), I decided to buy the wide wheel and tire.
The first turn I took I could feel a pretty big difference. The steering was "heavier" feeling, the bike needs more force to lean it over. It does actually straiten up faster though when transitioning so i would not say that it's slower when "flicking", but it definitely takes more effort. To me this tire feels more secure when going through a corner than the stock one, although I did have one "squirrelly" moment when all the way over scraping the right hand peg. I think it was because I hit some gravel which is plentiful right now on all the roads.
As far as traction straight ahead goes, it hooks up MUCH better.

The tire would not break loose the way the stock one does from a roll in first gear. I tried 5 times - each time it hooked and launched me forward with the front wheel first skipping then settling maybe a foot off the ground. Today it was around 65 degrees when I got out.....I can only expect this tire to hook even better during the summer.
So I feel (so far) like I definitely made the right decision, it hooks up great and the handling feels very good. It also looks great.
Mark