i think anima looks the coolest, and the illustration in the menu screen beats everybody else's picture..
i think a lot of people like the magus sisters because they have just about every skill on the sphere grid if not all of them, and once yuna is beefed up they basically are pretty unbeatable..
shiva was my favorite up until i had gotten anima, yojimbo was a little irritating for me only because the yojimbo trick didnt work for me, and i had only decreased the price to about 260,000 gil..
valefor kinda sucks, he doesnt really know anything and because of the temple he's in he isnt very powerful, or for that matter very useful..
ifrit was pretty cool but i just cant seem to keep him alive in battle, i had even taught him firaga to cure himself but after a while it doesnt help because of his low mp..
ixion is good but doesnt do a lot of damage and its accuracy is pretty low for an attack that quick..
bahamut was a disappointment, i can still remember the first time i played ff10 and had gotten bahamut and from his illustration thought he would majorly own but i was mistaken..
anima is in my opinion the coolest looking by far, the toughest out of them all (besides the magus sisters but give her credit, she's well worth the extra time for destruction spheres and is a great addition to both the game and my aeons) and has the coolest entrance and overdrive
im not trying to bag on the aeons just pointing out why anima is my favorite
