I liked the style of the original OVAs (probably because I watched them before I read the manga). You know, the ones that started with the gambler and went to the final battle with Dio.
The prequel (newer ones) OVAs had a different style. I didn't like it quite so much, but still didn't mind.
I'm more than halfway done with series 4. It's pretty cool so far (had to get used to the translation though - it's getting better as I go along at least). I like some of the stand powers, and the villain is interesting. I also like how Araki made up his own city, and makes "points of interest" and stuff.
I still haven't found a character I like as much as the ones in series 3 though. Kakyoin was my favorite, but Iggy was cool too. And although he was evil, Vanilla Ice was pretty awesome.
In series 4, I did like that guy who had the puppet stand at first (Surface)…I thought he was creepy (but funny at the same time - with how he got mad at his stand for getting all the girls), but then he just turned into a pathetic guy afterwards. But that happens a lot in the series, so no big deal.