+1
Pulp Fiction 10.0
Reservoir Dogs 7.5
Jackie Brown 6.5
Kill Bill (1 or 2, don't remember) 0.1
I also saw these in the same order of time and sort of started to loose interest after Jackie Brown. However, Kill Bill made it crystal clear to me that Pulp Fiction must have been written and directed by someone else entirely. Either physically or Tarantino experienced some serious trauma that changed his personality completely, sort of like what happened to Kinison or something else I don't know. Apologies to the Bill fans here, but there's just no other way around it.
Either way, Kill Bill was the last of his movies I bothered to watch, and should I happen to (knowingly) watch another one some time in the future I suspect the ultra low expectation would probably lead me to dislike it a bit less than I would had I not seen that Bill disaster beforehand.
Also I believe Tarantino wrote the script of From Dusk Till Dawn, which let's say wasn't for me.
Edit: I believe Tarantino had something to do with the script of both True Romance and Natural Born Killers (notice the time of release), and I liked both of these.