Saïx + Zero Gear + 4 Power Units = The Best.
Roxas + Zero Gear+ 3 Ability Units and 1 Sleight Unit + High Lv. = Fun.
Yuck. Saix with Power Units? Really? Give him 4 Sight Units and the Critical Sun and he gets upwards of a 50% critical chance. Every single finisher becomes a crit. He cuts through the Dustflier like a hot knife through butter.
I prefer Xaldin with the Pandora's Gear, 3 Ability Units, and a Power Unit (can be any; all are just +1 :\). He kicks some serious ass. His air combo takes off a good half of a bar from any enemy in the game, bosses take only slightly less. His ground combo has like three finisher-strength blows in it (meaning blows which stagger even the opponents which do not stagger) and is pretty sweet as well. Equip him with some Aeroga spells and he is nigh untouchable in most missions.
I never play as Roxas, simply because I played as him too much in Story Mode already. D: If I wanna use a Keyblader, I use Xion. She has the same stats anyway, and Dual-Wield Roxas is shitty. His combo strings are far too long and far too weak... You nearly always need to end them early to get any substantial damage done to enemies.
Xigbar with the Zero Gear is godly... Give him some Power Units and he can really cause some hurt. His range allows him to keep most enemies away. If an enemy gets in close, you can cancel out of his ground combo with a Y and backflip away, taking no damage. Just gotta remember to remove Sliding Dash and to have a high Air Dash equipped, as a lot of Xigbar gameplay consists of distancing yourself from the enemy to shoot them from afar. He could probably kick ass against the Dustflier. Haven't tried yet.
Donald is really really epic. I haven't played with Gears for him, though I imagine his Zero Gear weapon is the best. His spells do TONS of damage, usually cutting off multiple bars of health from the opponents. He doesn't need many of the usually standard abilities, so he's capable of holding a LOT of magic, Hi-Ethers, and Elixirs in his panels. <3
Lastly, Mickey with the D Omega. Every other weapon for him pales in comparison. This thing has a near-endless air combo which barely breaks between the end of one and the beginning of the next, meaning he can essentially lock his opponents out of attacks if they're in the air. His Magic is very high, too, so he can easily strike from afar with some powerful blasts of spells or up close with Blizzaga (my favorite~) and freeze them so his infinite-air-combo can deal triple damage.
