Sup, i'm Red Anvil, your average wiki user.
I have read jojo up to part 8 (except Stardust Crusaders) and watched the anime except for the OVA.
My favourite Jojo parts:
1. Golden Wind: best side characters and minor villains, only part that feels realistic in terms of character/villain motivation etc. 2. Diamond is Unbreakable: Best stands and overall great feel to it.
3. Phantom Blood: don't ask why, i just like it, also simple, unpredictable and unique.
4. Battle tendency: like Phantom blood, but not as good IMO, Joseph was a bit too over the top for me, and luck had too big of a factor in the bullshitty ending.
5. Steel Ball Run: average.
6. Stone ocean: good in the beginning to halfway, but some parts afterwards were not even worth reading.
7. Jojolion: so similar to part 4 that it feels like a badly made ripoff, instead of it's own good thing.
8. Stardust Crusaders: I have only seen the anime for this, unlike all others, it feels too repetitive with the plot of a Super Mario Bros game, character motivations are inexistant, most just explain the power of their stand, most interactions are forced just to go ahead with the plot, like Iggi's sacrifice.
Overall i would call this manga my second facourite and definitely a 10/10 in quality, if not for minor nitpicks here and there, in fact, i would give most parts an 8/10 at least.