I'm 4 years late to the party and watched this movie for the first time because I got burned out on Zombie films and didn't run to watch his movies anymore. I eventually watched all of his movies between The Devil's Rejects and this one, except The Munsters, and an hour into it I was feeling like I wasn't missing much. I wasn't hating it, but I certainly wasn't into it like Devil's Rejects, or House of 1,000 Corpses, which I just watched both in the last month and enjoyed, as I have dozens of times. But if you were to watch all three in one sitting, you can skip half of this this one and be fine.
It is definitely a Zombie film. Sheri is Sheri. She is maybe best in this movie than most other ones, but really her limited acting ability is clear. Rob's scriptwriting abilities are still limited to the genre he has rehashed from classic 70s Tobe Hooper and Wes Craven. There is literally nothing new in this movie you haven't seen before.
Sid Haig is there but briefly and that is sad. For me, he made both previous movies just a tad more awesome. The usage of Suzi Quatro's "The Wild One" was really cool and a nice surprise, but watching Otis being whinier and not nearly as scary as he has been before, was very obvious and off-putting while watching him. Also, seeing Otis laughing in Mexico was massively out of place and clearly forced. Much of Otis in this movie is not nearly as effective as before, even though he does a few "I'm the devil and I'm here to do the devil's work" kind of scenes. But he might as well just read Helter Skelter to a literary class.
By one hour into it, I was losing interest slowly and only finished watching to see what else was going to happen, but this movie didn't keep me involved in the story, or the acting like Devil's Rejects or House of 1,000 Corpses. Some moments were redundant and unnecessary, the movie appeared to be mostly just an exposition of the former two films.
Three solid stars. This isn't a garbage movie, but it certainly doesn't stand on its own, and it's not anything special. It's not great and maybe can be construed as just an average "good" if I need to give it a rating. Rob proved his worth with Devil's and Corpses, but this one just falls flatter than the previous two. It seems rushed and forced for all of the actors (except for the always wonderful Dee Wallace and the minimally available Sid Haig).