I have gone through 2 sets of RA1s in the front (and none in the rear) and changed the fronts to R888s. I would generally agree with the consensus here; RA1s are a little more bullet proof, but with the proper setup R888s can be better.
Personally, I bought the R888s shaved because I heard that I would heat cycle them out before I would use all the tread. On the other hand, the RA1s (I got them shaved) had amazing traction all the way until they chorded and I did occasionally run them on the street.
It doesn't sound like you want to go with R-comps so much any more, but if you do... get 'em heat cycled and shaved!!!