I agree with most points with Bahamut2000X. But let's see.


FF3j had the innovative thing of various summon attacks, and the summons looked cool too. This is also the first FF to have summoned monsters. They weren't useless at all. You can use Shiva to kill those FlameDevils in the Crystal Tower with one blow even if 3 of them get a back attack and each flame you. Bahamut is also an excellent way to destroy things. It's one of the most powerful attack in the game, as it does 3000-6000+ damage. Only HASTEd Shuriken does more damage

FF4 had pretty cool summons, though I didn't use them too much. Well, more than for FF6 at least. Bahamut is cool, especially against the last boss. It does 8000-9999 damage, and it's a lot faster to cast than Meteo. It also hits all targets.

FF5 had really useful summons. They didn't take much MP (especially the lower-level ones. the higher-level ones don't take much either, when you use Goldpins), and you can cast them for infinite times, and all 4 of your characters can cast them. In my first game, I won loads of hard boss fights by using 4 summoners casting Titan, or later Syldra, or even later Leviathan and Bahamut. And Bahamut is magnificent against Neo-Exdeath: it does 3000-4000 damage to every part! The only attack which could do more damage to Neo Exdeath would be GilToss.

FF6's summons had great story, but they sucked in battle. They also took loads of MP, and you could only cast them once in battle. Just like Bahamut2000X, I never used Espers in FF6 unless I was really bored.

FF7 had my favorite set of summons, but you can read more about that here. The summon spells are pretty powerful and I like to use them during boss fights.

FF8 had pretty cool-looking summon animations and for long they are the only ways to kill enemies, but I think the summon animations are too long, especially when you cast them hundreds of times during the game, in every battle. The effects are still really cool, IMHO, especially with Alexander.

FF9 had very cool summons too. I never used them much until I got Boost, because I wanted to do full damage with them. I wonder why I spared them so much. They would have done nice damage for not too high MP cost. Meh, I guess I was stupid and over-sparing. But the summon animations are really, really cool. And the amazing FMVs with Eidolons will take your breath away.

I won't analyze FFX or FFT summons, because I haven't played too much of those yet.