I do believe I've figured out a couple of reasons why I like Jojo's so much. Basically, it does two things right that a whole bunch of other animes, including Fairy Tail, does not.
1. That eternally overused and always lazy comeback device, the Power of Friendship, is gone or nearly absent in most of Jojo's I've watched so far, particularly parts 2 and 3. In Fairy Tail, it is a majority of the time that the main badguys outpower the heroes and have them on the ropes, but Natsu or Gray says something like 'I've got to do this...for my friends!' or 'We're Fairy Tail. Did you think you could beat me so easily?' and suddenly they're strong enough to beat the villains. In Jojo's, surprising turnarounds are accomplished not by PoF but by cunning and intelligence. Things to the degree of 'I purposefully allowed you to realize that I sneakily attached a grenade to your scarf so that you'd pluck it off and throw it away, thus pulling the attached strings and removing the pins of the six other grenades I more sneakily attached to you.'
2. In any given Jojo's encounter, the situation is usually extremely dangerous. The show's predilection for gore and tendency to always keep you on your toes feed into the idea that in any given moment, a battle could go wrong and the heroes are suddenly screwed. Allies can actually die, huge wounds can be made, and awful things can happen. In Fairy Tail, no matter how bleak the situation looks, you can rest assured that everything will be fine because Natsu & friends always win the big encounters. I can't think of a single heroic character that's actually been killed off, or any permanent wounds made. There are no corruptions, nothing like that. It takes a lot of suspense out of the fights and arcs. For instance, I never for once doubted that Fairy Tail would win the Grand Magic Games, because they're Fairy Tail. Lose for the first half of the week solid? Nah, they're gonna be fine.
And that's why. Cunning versus the cliche Power of Friendship to win some important fights, but there's a good chance in any dangerous situation that something awful might happen to the heroes.