I saw The Grindhouse last night...
Planet Terror: 9/10
This was so awesomely over the top, I was in stitches for the better part of it. "Uh, he's getting his... wet, Sir..." Rose McGowan looks great in it, and there's some great cheesy character acting.
Death Proof: 8/10
Tarantino has the ability to emulate actual conversation in his dialogue so incredibly well. This moved considerably slower than Planet Terror, but it may have seemed moreso only because you're watching it following Planet Terror, which hits the ground running. Kurt Russel's character is so well done, and his IcyHot jacket is just ridiculous. The entire car chase is just awesome.
If you take it for what it is, you're going to come out of this 3+ hour experience fully entertained.