My friend owns a differential shop in Tucson. When he first opened we put Dyneer no spin (detroit lockers) in our GM trucks. We learned that short wheel base and wide tires made for some interesting handling issues. If rear tires were not exactly the same radius you would have a push in one direction when accelerating and a pull in the opposite direction when decelerating. His blazer was a real lane changer with his 12.5 x 33s. My suburban had that size tire at first. Then a 75 mph hydroplane adventure had me changing to much narrower tires. While my suburban was not as bad at lane changes as the Blazer, it still had some push pull until I installed the narrower tires. The Dyneer locker has worked flawlessly for over 300,000 miles in two suburbans I owned. Still have the newer 87, I took that 14 bolt full float axle and placed it in a newer suburban!
Now days I would opt for a locker that allowed me to engage when needed. Can't tell you if the longevity is there with the newer designs but the option appeals. It you have a shorter wheelbase vehicle or use monster tires I would recommend you stay away from a full time locker.
