Stands themselves are pretty well done, but Part 3 where they are introduced is really only mediocre. The problem is that 90% of the arc is just "we are slightly closer to Dio's lair in Egypt and oh no there's another Stand User trying to stop us!" Additionally stands become so important that the fact that Dio is a vampire is almost an afterthought, despite the ridiculous power level of vampires in the first two parts. I also got really annoyed by the fact that Joseph barely uses the ripple at all. It's implied that he refrains from using it since the only vampire he fights is Dio and that only happens at the very end, but the first two parts showed that there were plenty of uses of ripple energy beyond fighting vampires (many of which Joseph himself came up with, and one trick in particular with the surface tension of water would have been useful during a certain gambling match).
In Part Four things get better, partially because the main villain gets involved in the story before the very end, and partially because the heroes spend a lot of time just dicking around town. It's a lot more interesting to see Josuke try to cheat at a dice game by using an Alien, just to piss off his rival, or use a combination of stand powers to try to win the lottery, than it is to see Jotaro face down the fifteenth stand user servant of Dio.