Bearings in the size and spec required for the rear wheel are cheap so any saving would be minimal by going to the cheapest available. Others have described them as cheap and nasty and the main cause of the failures. My suspicion is that inadequate tightening of the spindle is the actual cause of the failure by allowing the inner race to move along the spindle axis relative to the outer race and also allowing the spindle to move out of alignment which puts further loadings on the bearings that they aren't equipped to resist. I also suspect that Taiwanese bearing factories are very capable of producing good bearings, whether they did in this case might be another question.
