I'm interested in this thread since I'm planning to rebuild my RB-1 this winter with ultegra 6700 takeoffs and a 105 hollowtech 2 from Ribble. I already have most of the parts, and while looking into Shimano v. aftermarket BB, was disappointed to learn that the new Shimano BBs are regarded as seasonal replacements. The older Shimano BB was considered quite durable.

The SKF won't work with Hollowtech; I was going to go with a DA. Phil Wood makes bearing replacements --- not sure what else is out there that is compatible. I'm having a shop do the BB work, since this is not my area of expertise.