I have a few keycaps that would go to a RealForce, meaning they're PBT. They do feel harder and more "premium" quality than the ABS on the Type Heaven, and I do understand that many people generally regard the PBT as "better", but I did read somewhere or other that a good percent of people prefer the "softer" feel of the ABS (at least until they begin showing wear). I can't compare the typing feel since I've never used a board with PBTs and only have the Type Heaven. I can say, though, that on dragging my fingernail across the surface of the keys on the Type Heaven and then across the surface of the keycaps I have on hand for a RealForce, the ones for the Type Heaven have a more distinct roughness to the texture. That's "out of the box" though, and that may of course be a short-lived situation since, for all I know, the fact that they're ABS may mean it will start wearing down over time and may not take all that long to be obvious. In fact, well, it's hard to be certain but I dare say this already seems to be happening on my Type Heaven -- the keys with heavy usage are "apparently" smoother than the keys with little or almost no usage, and I've only had it about a month.
EDIT:
Having said that, they still feel perfectly fine and I wouldn't have noticed anything if I wasn't comparing the various keys. And it may still be rougher than the PBTs (I'm moving and don't know where I put them). The purpose the texture serves seems to still be fully intact, for now at least. Overall, I still like this keyboard a lot.