I have had the CrossContact LX20 (275/55) installed on my factory 20inch rims for about 2 years, 20,000 miles.. initally they rubbed a bit when backing up and turning, however as they have worn (or the plastic in the wheelwell has worn away) that has mostly gone anyway. I have been happy with the tires, and they have seemed to wear well.. I can see getting at least 50-60k out of them based on how they look today. They could be better in the snow, but so far are fine for the Upstate NY winters. I hated the factory Bridgestones.. they were junk, terrible in the snow, and were shot at 35k for me.
They are wider and look much better than the factory size on the truck. Because of this though, my fuel mileage has dropped a bit.. hard to say if the ECOPlus technology is BS or not, since i changed tire sizes.. however, I'd have to assume it is just marketing.
I'd like to get a more aggressive tire, however I am hesitiant due to the 7inch wheel width issue and compatibility with most tires... also, I really like the look of the wheels.
Hope this helps,
Jim