Perhaps not new releases but Every Time I Die's Hot Damn is pretty mathy, and Cave In's Until Your Heart Stops is mathcore+Slayer worship. Plenty of great bands have been mentioned, but 2 in particular deserve the opportunity to rule your ....ing life. Knut and Botch. Man those bands just have some dandy tunes.
The Math-Rock News is great, but I'm not sure it's relevant to the thread. There's a fairly big difference between mathrock and mathcore, even if they sometimes overlap (e.g. TFoT).