I had the opposite reaction.
I forgot why I never watched this movie when it came out, then saw this thread bumped back in April, which then made me decide to watch it. Going into it blind (outside of the last two pages about Lee), I found most of the movie to plod along like an average Tarantino movie, but it certainly wasn't special. I didn't even figure out it was about Manson's people until 2/3 of the movie was done, but then the retarded end happened and ruined it all; making it feel like some self insert Hollywood up it's own ass, auto fellatio mess.
I find Tarantino is at his worst when he does his stupid gore shtick verses his good/great dialog. So, if I were to rank this movie among all his movies, I would put it third from the bottom, better than Grindhouse and Death Proof (which I absolutely hate), but worse than Kill Bill.