Just saw the trailer for this; Tarantino looks to have a huge hit on his hands, if the trailer doesn't lie. BTW, this is an excellent trailer: outlines enough of the plot and characters and some action to communicate wjat the film is like, but doesn't give away the ending. And it is done with style and wit in the music and editing.
I don't know about over the top. Looks like a very linear, traditional plot line, really, it's kind of the same plot line as Nolte/Murphy "24 Hours" in a way... he's got a seventies "Mandingo" blacksploitation vibe superimposed over the spaghetti western genre'. What's interesting in the trailer is the music choices, which rarely match the actual movie, but with Tarantin, it is actually possible that he'd be crazy enough to DO such things, and that could be awesome. But that's more a Baz Luhrman thing.
I think it looks as flashy and violent and colorful as, say, Kill Bill was. Just little touches like blood getting sprayed over a cotton field lead me to believe there will be some grand ridiculousness taking place in this film.
And I'm not so sure about it being very linear, either. I avoid reading any major spoilers, and I'm not about to say anything that really gives anything away, but in my reading of and about this film over the last few months, I know there are several plot elements not really featured at all in the trailer. SUCH AS (and I'm not really giving anything away, as no one has seen the film, and no one knows any outcomes from it, but if you want to avoid knowing ANYTHING about this film, then maybe don't read the next sentence), the trailer didn't show much of anything about the side-plot of Calvin Candie's slave fighting ring (which features Don Johnson as his right hand man), or the adventures of Django's wife Broomhilda, who I've read will have a decently featured side story throughout the film.