I like the cage nut best. It gives you that last little bit of play. Sometimes when I was putting the darn things back together, everything just almost lined up, but not quite. The riv-nut cant be moved a millimeter one way or the other. WHEN, things line up just right, the riv-nut would be great. But that happens about as often as me drinking bad beer.
The self locking nuts are a grand PITA. You can tell how often a set has been repaired by taking a magnet and "fishing" in the bottom of a generator. Sometimes the results are fantastic.