So both The Heads Are Zeros and Neck First are from Maryland. They frequently play in Baltimore. The Heads Are Zeros' side straddles the line between dark hardcore and grindcore pretty well. They play really fast and are super technical, although I found myself loosing interest in the dizzying frenzy. If you liked Daughters, The Jonbonet, and other white belt grind you will dig THAZ (they should just be called thaz, honestly, that name is sick as fuck). Neck First, however, is a screamo / emotional hardcore band. I have heard great things about the bands' live performances, but these recordings don't do much for me. I like their side for what it is, but even at that I realized I only like it because it reminds me so much of Botch. I actually put on American Nervoso after going through the Neck First side a few times.
What I think doesn't matter though. Listen to the record and get yourself a copy. When the bands go on tour go see them.