I really like Poltergeist! Their first album, Depression, is probably the most bare-bones of the three. Behind My Mask is slightly more ambitious, but still very fast paced and aggressive. Nothing Lasts Forever still has plenty of rampaging thrashers, but there are some slightly progressive leanings on a few songs. It has more power / thrash moments than any of the others.
I actually like it the most as it is their most mature release. Not saying the others are bad, though. I like those as well.