Shamelessly bumping this... The RC24's seem to have sold out (at least for the moment), currently it comes down to this between the AL30s and the RC38s. The AL30s are £50 cheaper but 8mm shallower, apart from that and the supplier there doesn't seem to be a massive amount between them - I have no idea how much difference the 8mm will make.
Normally I'd go with Planet X as they have a very good reputation (and I'd never heard of Cycle Division before); however, in this case there seem to be some issues with bearings in the AL30s which Planet X fix by sending you the bearings to fit yourself (at least according to a variety of forum posts). The few posts I've found regarding the RC38s seem pretty good to me...