I've had Blizzak WS-80, WS-90, and currently have Continental VikingContact 7. Overall the Blizzak WS-80 had the best performance, but the good part of the tread was toast after 2 winters. Here in Colorado we get periods of dry weather between storms and it just caused it to wear super fast. The WS-90 lasted an additional winter longer than the WS-80 before the good tread was gone.
With the VikingContact 7 I am going on the 3rd winter this year with them and they seem to have plenty of tread left. I'd say they aren't quite as good as the Blizzaks were when the Blizzaks still had the soft compound layer, but they are still very good and so far they have been lasting given the wide range of road conditions we have in the winter, not to mention temperature swings.