i personally havent had alot of luck with the powertrax no-slips. it could be the guy that installed them messed up (like shaving the damn pin

) or i got that 1 in a 1000 defective product. but when they do cooperate, i love em. my front worked flawless for over half a year then would suddenly not unlock anymore. the back has pretty much been messed up from day one when the guy shaved the pin. i put a whole pin in and shaved a gear tooth, and it helped a little. i'm hoping putting a new spring pack in will fix it for good. thats what i'm doing with the front. so we'll see sooon if new springs will make it lock and unlock properly again.
but what i'm gettin at is my next lockers will be selectable. i'll most likely go with an electric one or the ox looks pretty good since it is cable selectable and not air or electric. as far as i know, they only make the ox locker for the d44 high pinion, but i could be wrong on that. i havent investigated them deeply. oh and they come with a beefy diff cover.
it kind of comes down to budget tho. i hear good things about the aussie, like i heard good things about the no-slip. but the no-slip has kind of let me down. lunchboxes are 3-400 and selectables are 700+ (and dont forget that arb's need the onboard compressor too (but you usually get a free compressor when you purchase 2 lockers))
edit: selectables also replace your carrier, so you have to get your gears set up again. so if you dont know how to do them, or dont have a friend that will do them, it gets expensive to add them after you already have your gears set up.