I've definitely read nothing but not great comments about the d50, but I really couldn't pass up the deal I got on the axle. It is a unit bearing, but I do have manual lockouts-I haven't taken them apart yet, but the bearing assembly is supposed to be separate from the hubs. The big weak point on the d50 are the inner shafts. They go from 1.5 to 1.3,30 spline-same as my d44. I'm planning on running 38's, which coupled with my sissy right foot should hold up ok. My long term plans, are when the d50's r&p give up the ghost, I'll either swap in my extra hpd44 housing, or a 9" center section.
I do have a pretty awesome hpd44 under the XJ now. (1/2" axle tubes, welded on wedges) I originally wanted to go 35 spline rear,5.13 spooled, top and back trussed 9", 33 spline, 5.13 spooled, trussed hpd44. But for way way less than what it would have cost to build that, I got the d50/10.5 geared at 5.38, rear has a detriot and front has a lunch box locker. The 10.5 only has 3/4" less ground clearance than my non-shaved 9" and is in a totally different ballgame as far as strength-10.25" ring gear, FF 35 spline shafts, ect. And we all know the d50's downfall-R&P and inner shafts. So I may have a bastard axle, but I still feel that I made the right choice.