Ride the Cat and Fiddle onna Sunday daytime? Not for love nor money.
YMMV
Motorbikes?
Yep, despite the fact that the pub is closed and there's average speed checks and airplane monitoring its still a bikers mecca with lots of looneys on it. The descent is fast enough, you can easily hit the 50mph limit, and technical enough on bicycle that you want the full lane, some of the bikers don't share nicely.
It's must ride road though, my preference is dawn on a summer Saturday, no bikers, no commuters, no heavy wagons, just stunning. Last time I rode it I think I saw 3 motor vehicles between Macc and Buxton.
EDIT: that would be the last time I climbed it, the last descent was Venetian Nights and I'm slow enough that it was evening and dark