It all depends on the platform, GC/GD/GR/etc, and the suspension spring rate. Too big for one car might be too small for another.
I love my 22mm F&R setup, and I even wish I had a slightly bigger front bar, but the slight oversteer when pushed is fun.
I actually had a 19mm rear and decided to go bigger. Now I'm looking at actual springs & struts...
In the snow, I could only see it being an issue if you weren't paying attention. I personally love it. With a little left-right flick of the wheel and some throttle, the rear end will step out on command, but in a very well mannered and controllable fashion.