i never used titan, i just wanted to get him jsut to have all the summon materia. and i actually used choco/mog summon earlier in the game because it caused paralysis or whatever you wanna call it and i used it tons against Lost Number (the enemy before you get vincent when you open the safe) and it proved to be really useful, even if it wasnt' that strong. if i ran out of mp or turns to use choco/mog i would use aeris' seal evil which is the same except causes silence and it doesn't do damage i dont' think...