I'll only be using them on the RS trackdays, they are the only day's I'll do for a bit really. I know they are useless when cold, you can come off just doing 10mph.
Just need a lap or two warming up and then they are usually okay. Just the same as you do with normal tyres, they don't get any good until you've done a few laps. I've worked with slicks before, so I know how bad they can be if not warmed up.