I went to a screening this evening. It was really great, but nothing like Cabin Fever. It actually follows a pretty coherent storyline, and there aren't many funny moments in the second half. He takes the film and the genre seriously this time and proves that he's quite fucking talented.
I wish I could explain some of the movie to you, but knowing anything going in would probably ruin it. Just know the film involves hostels, Europe, and pretty hot women - for some length of time. There's no supernatural element, so no, no From Dusk Till Dawn-type things go down in the hostel. Just expect lots of gore, lots of sex, and frequent laughs.