Well I have the trxu's and they are at about 15,000 miles. They have lost about an eighth of their tread so far. They perform fantastically off road in just about any conditions. They are siped so they do outperform the bfg m/t's on wet pavement.
A few things you have to keep in mind though when you get any kind of mud tire is that it is a MUD tire. You will have to contend with vibration coming through the gas pedal. They will make noise as you drive down the street. Even siped mud tires still do not grab as well as street tires in wet pavement. Mud tires dig big holes in any kind of terrain when they spin. You cannot spin on loose terrain trying to get traction all that you will do is dig a big hole. Your spare will look goofy if you put it underneath the truck. It will look like the X is pooping. Regardless of the brand, a mud tire will wear faster than an all terrain tire.
That being said, I went with mud tires since I wanted the added performance off-road and the look. The trxu is a great looking tire it definitely looks mean on the X. I personally love them and after the double lift I will probably get the same tires in a 33.