Quina is the only Blue Mage whose magic I have fun collecting and use frequently.

Strago, I mostly wait for the end of the game to fight Dark Force, an enemy that has the majority of the spells (of course, some I do get on the way, to make the job easier). Still, I don't use him much, let alone his Lore.

Quistis, I like how you get the magic through items, but her Limit Breaks aren't something I ise that frequently either. However, I do use her White Wond one frequently in boss battles now, ever since I found out how to get it. Degenerator is also a pretty good of her spells, just too flashy for my like.

Kimahri's spells, I'll be honest, aren't really that useful with the exception of those that cause non-elemental damage, which would reduce all to Seed Cannon, Thrust Kick and Nova (Jump isn't a blue magic). Having the other abilities is cool, but they just don't do the trick as well while they're Overdrives, imo.

Tough call. Quistis, Quina, and Kimahri are all high up my list, and gameplay-wise, Strago only has to see an enemy perform blue magic to learn it.

I always missable I should careful kimahri for example thrust kick this can be lancet by 2 bully ronso and same happen nova for omega of course I always forget