If you go the Powertrax route, buy just the regular Lock-Rite and not the No-Slip. The No-Slip is junk, I have run one of them before and it NEVER acted right, horrible waste of money compared to the Lock-Rite which I've also ran in a different truck.
I'm running a Spartan locker in my front axle (Dana 44). It works great and I haven't broken it, so I guess I like it. It has a few less parts than the Lock Right (which I used to have in another truck and also liked), which is kind of nice, but I don't think you'd go wrong with either.
I run one in my front 44 with 39's and it works good, my lock-right in my 9.25" was the best in terms of feel and quietness, my Yukon grizzly in my 14 bolt FF can be temperamental. I've never had any mechanical failures of any lunchbox lockers.