What he said.
I swap between schwalble blizzards and ultremos depending on the weather or my mood. In summer I've no problems commuting on 'race' tyres, in winter I just accept I'm going to have to back off a bit. The summer tyres still do enough miles that they don't need replacing, I'm more bothered about puncture protection.
There's a propper set of switchbacked hairpins* near work (yes, south of the M4 in Berkshire!), and I'm often amazed quite how much you can push against even on the winter tyres, any sliding I do is almost invariably due to something else (diesel, gravel, leaves, white lines). No doubt the ultremos are better, but 99 times out of 100 both are fine, the other 1 in 100 nothing will help you.
*even better, they're trafic lighted, so you know there's nothing coming the other way!