I just bought a PowerTrax Lock-Right, But now that i look at the PowerTrax No Slip Automatic locker it looks like it might suit my needs a little better.  It says that the no slip is quieter, not as much backlash/windup. I figured it would be better to swap it now for only $150 more, then put in the lock right and not like it or be able to return it.
Does anyone know how big of a differance there is?  And I know, just put a posi in it. But I have my heart set on a locker, plus I had the Rear end rebuilt about 1k ago and i dont want to fiddle with the shims.

Thanks  

no matter which one you go with,you will most likley have to FIDDLE with shims.BTW get a good posi.  

I ended up blowing up the spider gears doing a burnout and was forced to put in the Lock-Right. I love it, the only time it makes noise is in a parking lot when I whip into a parking spot with my foot off the gas.
As for driveablity its fine. The only place i notice a problem is trying to turn under WOT, like going up on on-ramp on the highway, it under steers.  But all that means is I need to get a Big Block to put more weight over the front end.