NO SPOILERS:
I caught it at a screening this morning, and was absolutely blown away. Though I haven't read the graphic novels, the whole thing absolutely and utterly comes across like a (long) graphic novel brought to life. There are no "panels" in the bad sense, but there are lots of shots, stuff with shadow and facial wrinkles and that kind of thing that absolutely scream "graphic novel" while fitting perfectly into the overall film.
I gave it a 9. There were a few awkward moments, a couple of times where the scene went on too long and a couple of times where the action jumped just a bit too much to easily follow, but overall it was simply amazing.
It is very gory, lots and lots of blood, though the bulk of it, interestingly, isn't red (a fanstastic stylistic choice). There was puh-lenty of titillation, and while at the beginning it seemed a bit funky (there are extended scenes with bare women's breasts in the first 15 minutes), after a while it felt like it really fit well, and when you'd see yet another fabulous body in an incredibly provocative pose, it blended seamlessly with everything else.
The three stories fit together very nicely, interweaving with style. Tarantino's influence was obvious (he's listed as "Special Guest Director," and I can easily guess which section he helped with or even directed), but it was a combination of his and Rodriguez's style together that, surprisingly, meshed so well with the noir setting.
Color use, or more specifically the general lack thereof, was really awesome. All of the actors were great, really great. I don't like Mickey Rourke -- I actually quite dislike him -- but he was freaking fantastic here as Marv, one of the main characters. Lots of makeup, but stunning.
And for those who have mentioned concern that Jessica Alba might not look so great as a blonde: va-va-frickin-VOOM! Man, she was stunningly pretty and sexy, and I don't actually like her very much. I really look forward to the DVD for some freeze-frame fun. Wow.
So, to sum: incredibly stylish, shockingly (but entertainingly) gory, hip-grindingly sexy, fascinating stories, and one hell of a ride. Highly recommended for anyone who likes those things in a film. (aka major fanboy material)