Shaun of the Dead should be good, I think it's pretty much a perfect movie, and Edgar Wright's best work (Hot Fuzz is all over the place, with a few brilliant moments, and DIF have already pointed out all the flaws with Scott Pilgrim).
Planet Terror I have no love for though. I kind of hate this entire wave of "fake" grindhouse movies, full of shitty green-screen and cgi bullshit and purposefully winking all over themselves.
I vastly prefer Death Proof, which while flawed, feels like an actual movie from the time period (bad pacing and all) and that has characters and a point. You can have a crazy movie that goes all over the place, but the characters have to feel like they believe in the universe they exist in (perfect example being Big Trouble in Little China), and not like actors having fun winking at the camera.
Honestly, I kind of feel like El Mariachi and Desperado were flukes, cause I've pretty much totally disliked everything Rodriguez has done since then (except for From Dusk Till Dawn, and Tarantino's half of that movie is vastly better than Rodriguez's). For a guy that's all about old school genre movies, he uses green-screens and CGI almost as much as George Lucas.