I made Serah really dumb and one-track-minded when I played through, so for any time it presented me with options, I'd always pick the one that talked about Lightning no matter what the others were or I'd go for the really stupid/silly ones. (Which, apparently, are the best ones to pick anyway?) That made me feel better about having to pay attention to her. :P
I've gotten into the monster system and it's not as damning as I expected. However, I'm still totally unsure how leveling them up works - mostly like, when should I be using items that level up everything, ones that level up magic, etc.
You should base it on what the monster is good at. I think the "levels up all" items are a little weaker than their focused counterparts so if you're trying to boost a certain stat for a specialized monster, I'd leave them for last and do the focused ones as long as possible. If that's not the case, though (and either way, really), then it doesn't matter. I didn't pay that much attention to what I was using on monsters and I never had a problem with their stats. If you're super serious about having the best possible monster, I'd look into it in detail but if you're just playing through casually, don't fret over it. :P
