I and pretty much good with every character, I got them all mastered and have a firm grasp on their meta game, but I've also sunk 400+ hours into this addictive as hell fighter. But as for my top characters well:
Golbez was my first main because he fucking owns. He's the perfect balance between speed, range, attacks, and combos. Golbez's combos are as insane as Jechts if you got you timing down right and know all about dodge canceling and how his attacks link into each other. He's also a hard character to counter sometimes due to his attacks having some awkward angles. Also Cosmic ray is fucking epic.
Gabranth, oh my dear Gabranth what a monster I turned you into. With the right gear build you can keep Gabranth in EX mode indefinitely throughout a battle, which is precisely what I made him. Screw damage multipliers and all that junk, he's supposed to be stacked with EX multipliers and EX force absorption extenders. With the ultimate EX build, as long as you keep attacking, all the EX force will go to you and EXP-EX force perk on just sweetens the deal. You don't NEED any sort of stat boosters seeing as his EX mode makes him do beastly damage as it is, and his speed makes him soetimes difficult to block. All you do is EX burst cancel when doing HP attacks and save that burst for the final blow. Gabranth is a true monster if you build him right.
Jecht, the man you want to master if you are the crazy rushing type fighter. His combos are brutal and his deflecting palm attack is a great mind game and defensive ability. his combos are the most satisfying to pull off and really makes you feel like a bad ass when you whoop ass with him. The absolute definition of an offensive fighter, not to mention full of pure manliness.
EX-Death, the great brick wall of death. I'm sure most people hate EX-death sue to his steep learning curve and the fact that he's slower than the second coming of christ. The pure defensive fighter and the absolute definition of the word. I love this evil tree to bits. His guard-counter meta game makes him so unbelievably dangerous in the hands of a skilled player, that he is quite literally the strongest fighter in the game. His guard properties make him almost impenetrable and forces the offender to approach with sever caution. He's just simply awesome oncen you know what you're doing with him, plus Neo Almegist is awesome.
This three are the top 3 fighters in the game for me. I still love using Cloud, Sephy, Squall, Tidus, Terra, Garland, ect... They're all fun to play when you understand are attune yourself to their play styles, but THOSE 3 are terrifying monsters of death that stack up to being some of the greatest characters in ANY fighting game.
Yea...as you can deduce from all this I simply adore the game. It's one of the best fighters to come out in a LONG time and it's unique nd innovative game play is a breath of fresh air in a genre that more or less FEELS stagnant, even though it's not.
