Well...... I have run Blizzak ws80's year round for 2 years. Yes, they wear a bit quicker and
they are a bit softer and don't provide quite the performance.
If you lived where the summer temps reach into the 90's and above then NO I would not do it as they will wear out even faster at higher temps. But I live at 9,500ft above sea level in the Colorado Rockies where summer temps rarely reach 80 degrees, and the winters see more than 300" of snow. I have gotten 25,000 miles out of Blizzaks running them year round, 2 full summers and 2 full winters. Frankly, I never seem to get more than 30k out of a set of tires, no matter what kind they are.
i picked up 19" santa fe sport rims (gunmetal grey) which looks amazing + hankook icept evo 2 245-45-19 winter performance tires and so far they are great on dry road. no snow yet in Toronto so cant comment on snow/ict/wet conditions.
I didnt notice much difference in driving from my summers to these winters on dry roads. usually winter tires are sluggish.