How do you like those Q78s?
There are several options for axles and u-joints in the D30 that hold up better than the stock setup. The guys who are toughest on their junk seem to think that the Warn shafts are the best out there. FarmerMatt managed to trash one recently, but that's the first one I recall ever hearing about. I believe that the Warn outers only work with their replacement hub set and not the stock unitbearing. Yukon and Superior make well reputed alloy axles for the D30 as well.
The CTM u-joints are practically unbreakable, although pretty pricey. They're an extra-beefy alloy joint that replaces the needle bearings with a bushing und use full-circle clips. They require regular greasing but really hold up. Good things are also being said about the Longfield u-joints. They are a standard Spicer 760 that gets a special heat treat and a cryogenic treatment, as well as bushings like the CTM. They are significantly less expensive than the CTMs, I think along the lines of $70 a piece. I've yet to hear of anyone using the OX axles or joints.