what's the best sure grip for a 8 1/4

I saw there is a powertrax lock right 27 spline locker on ebay right now for $175. The thing I like about that is it goes in w/o messing wiht the ring and pinion settings. I'm sure it locks up real solid. The down side it might not be the best thing around town. I don't know the difference in performance between the auburn style and the Dana trac-loc style factory setups but the trac-locs are way more common on ebay.