If you need an air locker now go with ARB.

Tomorrow Eaton's E-Locers would be the way to go.
They get rid of alot of the problems of the ARB.

The drawbbacks are that they aren't proven and Eaton keeps pushing the relase date back.
6 months ago they said they would come out in spring 2002, then it became fall 2002, last I heard was spring 2003.

Since I wont have the money for a year or two anyway, I'm willing to wait. Till then I'll struggle offroad the way I always have...
with luck.