I have a screener copy of Cabin Fever (courtesy of my friend at Lion's Gate) and it is a very good movie.
Something tells me it's going to get dissed at the box office, though, simply cause a.) it's opening against Once Upon A Time In Mexico (sequel to Desperado) starring Antonio and Johnny Depp. Plus b.) everybody keeps touting this as a return to old-school horror.
This is NOT a straight up horror film trying to get an old school feel a la Wrong Turn or House of 1000 Corpses. It IS a very cool tale of paranoia with a twist of splatter and a huge helping of David Lynch-esque weirdness (the director Eli Roth is a veteran of Troma and Lynch). Actually, that's probably the best way to describe this movie - Troma meets Lynch.
A very good movie but don't be expecting a serious horror film.