I went down twice today. Once from rear wheel slip and the other front. Both on moderate hills featuring glare ice covered with a thin layer of new, loose snow.
Granted, that's a slippery combination but the studs didn't seem to be grabbing much at all. The tires are rated at 65 psi and I had them inflated to about 45 or so.
Too few studs I'm thinking. In past years I've used Kenda Klondikes and it's not like they're perfect in all conditions or anything. But they seemed to have little trouble on ice.
On flat surfaces the Nokians seem to be OK on ice.