It isn't often that I come across a movie as middle-of-the-road as this one. Everything about Night Feeders is an exercise in averageness. The plot is a straight off the shelf sci-fi template, and the script reflects it. The acting wavers between strained and passable, especially in the case of the oft-unintelligible redneck character of Donnie. And the special effects range from downright laughable to borderline-competent. There's nothing about Night Feeders that sucks badly enough to make me hate it, nor to make it prime MST fodder. But at the same time, there's nothing very noteworthy either.
There are certainly worse films to kill time with, and if you're hard up for riffing a cheesy movie, and you don't have any alternatives, you can probably get a laugh or two out of Night Feeders. However, there are plenty of sci-fi horror flicks out there that are either more involving or more joke-able than this very average film.