Top Three (in no particular order):

Anima-Best looking, and she is the only one with a known backstory, and a decent backstory imo
Bahamut-He rocks, is the first to have BDL, and the kid Fayth is a great character
Shiva-Cool looking.

Bottom Three (in no particular order):

Valefor- Quite dull
Ixion- Again quite dull
Yojimbo- I really don't want to be paying him gil...