I've done a little research on the Detroit electrac and it seems like a better deal than an ARB because when unlocked it still works as a posi unit. The ARB is just an open Diff. Now that said IF you have much snow and ice in the winters you want the ARB 'cause that open diff in 4wd front and rear will help you stay in a straight line 'cause only one wheel is spining at each axle. Even a posi can get pretty squirly on slick snow or ice. I'm sure a lot of people will disagree and say "the more traction the beter" but I have first hand driven a 2wd open diff truck on ice better than the cherokee in front of me that had a rear posi, he was all over the road. You may want to check on the OX locker too. I like the simplicity of a cable accutuated locker. Mechanical is almost always better than electric or air in the enviornment we put our trucks through.