No idea about the Powertrax models, but I can say this... "They're no Detroit" !!!
Lockers are great traction-aiding devices. But with everything you do to make your off-roading more enjoyable and more capable you have trade-offs for road use.
For instance. Rain. On a rainy day you have to be really careful when turning corners. If you put too much power into the turn the locker WILL lock up and you'll end up going sideways. It'll take some getting used to but it can be used to your advantage.
They will also wear your tires out a little prematurely, because you'll have both tires under power more frequently, as opposed to an open differential where the power transfers back and for depending on the torque split and wheel spin.
If you plan on doing a LOT of off-roading, both 4x4 and 4x2, get a locker, like Detroit, Powertrax, or ARB ($$$). If you do a lot of street driving I would recommend either the ARB again or some sort of limited-slip differential. They are more road friendly and cheaper to buy.
A locker in a 4x2 is probably the best best for traction off-road. Most off-road racers will run a spool in the rear end which will give 100% traction to both tires. This will not work on the street as the tires need to be able to rotate at different speeds to handle turning, etc. Off-Road, you just sort of power into it!
Hope that helps. I'm getting long-winded in my old age! [img]/wwwthreads_images/icons/laugh.gif[/img]