I run a 190/55 religiously. Yes, it's a 600. No, I don't have any untouched rubber on the outside edges of the tires. I feel a need to mention that because those not "in the know" tend to make uninformed comments about having too big of a tire on a "little 600." Most of them being on 1000s, 180s, chicken strips. ANYHOW, it turns in deeper which directly converts to faster corner speeds and less trail braking. More contact patch in the corner leads to an ease of adjusting in the corner with confidence.
These are all IMO, but unless everyone I used to ride with got slower a week after I upgraded my tires, then everything I say is true for me.
I have a shiny new 003r/s in 190/55 (and the respective front) coming to me this week. Woo!