I love these and am buying another pair in case they stop making them.
Note that Sportiva uses a variety of different rubbers on their mountain running shoes, and they are not all the same. Though not as sticky as the RS on their true climbing shoes, the XF rubber is a durable climbing rubber that can handle 4th class and easy 5th, while still providing the comfort needed for those 5+ mile approaches.
Sure my Gandalfs climb better, but by mile 3 my pads are bruised out. These are the ticket for long Sierra traverses.
I added a superfoot orange footbed and I've had no problems with my pads, and I've been 100% blister free. I haven't had the problem with the tongue slipping to the side like others have discussed.
I've used these for 10 mile trail runs near the coast as well as a few all-day Tuolumne traverses. I've been surprised by how well they endure scree skiing and general abrasion.