Rockwells seem to be pretty popular with the east coast mud runners, not so much for the rocks. Just too big and heavy, plus the toploader layout makes for interesting packaging. Portals are all but nonexistant in competition these days, I think only Jennifer Little is still running them. Biggest problem other than breakage is that its really difficult to package a vehicle around them without having a pretty high CG. I dont think I've ever seen a stock framed vehicle on portals that wasn't stupid tall. Even most of the buggies built around them have a far higher CG than standard straight axle rigs. Plus if you run mogs you have the added challenge of that HUGE pinion.

Now that you can build a 60 from scratch from a number of suppliers they seem to be the axle of choice for just about any type of use.

Dallas