Button rifling=conventional rifling. Like the kind you would see in any normal bbl (handgun or rifle). It will have the deep groove or "valleys" in it. Poly bbls are different in that they do not have the grooves. The poly bbls are shaped like a hexagon (six sides in a HK, eight sides in a Glock). I like 'em a lot better. Much easier to clean cause there are no grooves to clean out. HK's bbls are also cold hammer forged. Same way they make the cannon bbls for tanks.
I believe that you can not shoot lead bullets out of a poly bbl. You must use some type of jacketed bullet.
CCF bbls are pretty damn good from what everyone here says. Lots of happy customers form them. I've got all .45's. I'm sticking with the poly. If I had a .40, I'd seriously consider keeping the bbl poly if I wanted the o-ring and threads. Just a personal preferance.