Oh god, this is like the wine equivalent of PC vs. Mac
PCs are better obviously.
Corks can dry, fail, leave bits in, etc. Caps are normally a better seal.
There's probably some argument for corks - tradition, some other shit I can't remember. Google for discussions about each option's merits.
Cork is harvested from trees without harming them, and isn't processed much, so it's a pretty sustainable material.
(I don't really drink wine so no opinion on that side of things)
So there's no particular advantages of cork over cap?