Holy, I think the rating is misleading because the the style has the potential to turn people off, but I'm on volume 3 and can attest that it's all good fun. I think you just have to modify your expectations for the genre. The only things that really suck are the university characters but who cares: we get to watch them suffer at the hands of some superhuman mutant things in gnarly gore goodness.
Edit: This is the best written-by-an-insane-author manga I've read. A lot of it doesn't make sense, but it's a roller coaster filled with action and excitement.