First year I had my tracker I ran all over with both ends open, never got stuck. After installing a locker in the rear I stopped worrying about getting stuck, it really climbed good. Then I got an ARB for the front, it is awesome. Climbs better even without locking it, and when it is locked up it just goes. Steering is much harder when it is locked, and seems that it would be a long day on trails to have that kind of steering whenever in 4X4. With an ARB, or E locker it is just a switch away from locked to open. Pricey, but worth it if you are going to lock the front.
I would recommend puttting a locker in the rear, and if you are not experienced with setting it up, HAVE IT DONE. If not set up correctly, it will buck and kick when turning and may not function when needed. As light as the kicks are, some lockers will jump when releasing anyway.