IT BEGINS And yes, JJBA works both standalone and as a total story very well. [With the exception of Part 7, which is a reboot and thus the prior parts do not matter]
Also each of the parts is a significantly different genre and setting, with the main character being very different in personality and even fighting style. So while you may not like, say, Part 2's style, Part 3 may work for you. And so on. Araki is awesome like that. Part 1 [Phantom Blood] feels COMPLETELY different to Part 2 [Battle Tendancy] and Part 3 [Stardust Crusaders]. Johnathon, Joseph and Jotaro are completely different characters.
I hope two things:
1: They remain as faithful to the manga [Barring needed Censorship, and I imagine there may be a fair amount of that in Part 3, such as Tower of Grey] as possible
2: The animation quality is a little more stable than the last season. They should be better now, and have a larger budget due to the success of Pt1 and Pt2.
Still, if you want to see what might be the most faithful adaptation of a manga into an anime ever, and a classic one at that, give JJBA a spin.