Well I personally can't stand Metalcore, to me it's whiny, wimpy, pathetic and boring (there are a few bands out there that stand out though). But I do like Deathcore, Grindcore and other genres with Extreme Metal and Hardcore influences. Also I do consider it Metal (Deathcore, Metalcore etc.) as much as I hate having other kids coming up to me going "OMG Amity Affliction are sah BR00T4L!."
But I guess if I consider Nu Metal as Metal than I guess I really have to consider Metalcore Metal. There aren't any Metalcore bands I like but there some quite sick Deathcore bands out there like Veil Of Maya, Thy Art Is Murder, Rings Of Saturn and Impending Doom.
Some Deathcore I enjoy:
Reign Of Darkness by Thy Art Is Murder
Awesome Deathcore from Australia with great production and some really unique tunes that aren't the typical generic ones you hear all the time. I do have one problem with these guys, well more so the fans because many consider them Tech Death which I completely disagree with. They are Technical Deathcore (I personally don't think they are that Technical)
Murderer by Impending Doom
I personally think these guys should be the standard in Deathcore like Cannibal Corpse is to Death Metal, sure they're a Christian Metal band but does that diminish it's quality? But I still prefer Thy Art Is Murder and Rings Of Saturn over these guys.
Galactic Cleansing - Rings Of Saturn
Now this is what you call Technical Deathcore! The reason why I love this band so much is because I love technical wankery, it's why I love Necrophagist, Yngwie Malmsteen, Spawn Of Possession and other bands with insane technicality.
Now remember this is all personal opinion so don't get your panties in a twist if I somehow managed to annoy/offend you.