It is the exact same one as in Win7. It is a paid add on unless you get it quickly. MS has a site where they are giving it away for free until January. Also, you must have Win8 Pro to install WMC at all.
An update. I used the live chat again today - the first tech I spoke to actually lied to me. If it does not install then something is broken on the PC - it is not a known issue. The tech spent 4 hours trying to fix it (remotely controlling my PC) and failed, so he is having a tier 2 tech call me and work on it on Monday...that is if PA is still around after the hurricane hits.