So far they are wearing well. That is the best tire I've ever owned, the tire flex around rocks and traction is outstanding...... I ended up getting both back wheels caught between two huge boulders while running Strike Ravine in Moab about a month ago. The tire pulled a full inch and a half away from the wheel without losing the bead...... incredible.
Absolutely get the Cognito kit! I installed the idler pivot kit also because of the big tires. I have put that front end through hell since I added all that, and have had zero problems with it.........yet.
