Having had the work done, I would say the 98 RC36 is a far superior fork to the Z2 Bomber, the only drawback being that it needs more maintenance.
Looking at this assertion again, I think I should really have qualified it by saying that I weigh ten stones. Some people find the RC36 under-sprung, and perhaps it's not surprising that I don't agree. Tim says that even he has no extra-stiff springs, although I think he said he was trying to source some from another manufacturer.
Also the heavier you are, the more you would find advantage in the Z2's 30mm stanchions over the RC36's 28mm. If you are 15 stones, I imagine you might prefer the Z2. Somewhere in between those two weights, there must be a tipping point, but I don't know where it is.