JoJo’s Bizarre Adventure Part III: Stardust Crusaders is better than Parts I and II in almost every way imaginable.
Part I: Phantom Blood introduced a forgettable lead, incompetent side characters, a lousy power system, and one crappy fight after the next. It’s only saving grace was its charismatic antagonist.
Part II: Battle Tendency gave its lead some much-welcome charisma, but it also brought in more incompetent side characters, pushed the flailing power system to its death throes, and with few exceptions featured fights that were every bit as crappy as Part I’s.
Part III addressed every criticism I had of Parts I and II. (I love it when authors listen to me.) Stardust Crusaders brought back the best characters from Parts I & II. It made its side characters relevant and useful. It threw out a failing power system in favor of one that had plenty of room to develop. Part III didn’t completely outgrow its predecessors’ penchant for idiotic battle tactics, but it improved significantly.