I live at 7,000 feet in Colorado on a dirt road (and 100 yd gravel driveway.) We've just been through one of the most extreme winters in decades, with -27 temps and plenty of snow. My wife (a nature photographer) and I also drive extensively around the USA, often in bad weather and to... unusual :) destinations.
These tires have been incredibly wonderful, restoring the sense of rock-solid reliability on any road surface or weather conditions that I used to get in our old Subaru Impreza. I did notice a small MPG hit compared to the OEM tires, perhaps 2mpg, but that's a price I am willing to pay.
Now after 35k miles, I am sensing the tires will not come close to the 80k mile warranty. That would be sad, but I'm not willing to give up the performance for more mileage. I'd rather be able to drive safely and avoid sliding into a ditch or another vehicle :)