Yeah, when I tell people that Jojo's is over 750 chapters long, they tend to seize up a little. (Although FMA's chapters are about twice as long as Jojo's, so that's more like 172 chapters if you put them on equal terms. Still nothing compared with Jojo's, though).

There's also the fact that...well...Phantom Blood does not start well. It picks up a lot once Zeppeli enters the scene, but the beginning is just straight-up boring, and Dio doesn't even start showing his Magnificent Bastard tendencies until about halfway through.