Yeah, I'm not sure...I mean, it was bad, but it was trying to be. So it did a good job of being bad, so is that bad or good? As you say, they really nailed the grindhouse thing. I think I personally don't really like the grindhouse thing all that much. If it was the same thing, but add some supernatural/horror to it or fantasy/sci-fi and I would have been right on board. Personal tastes.
I didn't hate it though, and it definitely had moments I liked. I would watch it again, but wouldn't go out of my to see it.