Many enemy skills rock (like the aforementioned Trine, Beta, Big Guard, etc.), but some can be missed, wheras with magic materia you just have to get them in the first place and then you're okay. Enemy Skills are easier to obtain if you know where to go, but some (Chocobuckle) are frustrating. With Magic Materia you just need patience, 2xGrowth weapons/armor, and a good spot to train. Bottom line, I use both Master Magic and E. Skill to kick ass. Use their strengths to cover each others weaknesses.

Raistlin, what's your take on FullCure and Shield? FullCure is just a 100MP X-Potion (almost useless), but Shield is unmatched, since Aeris is (SPOILER)unavailable to use her Limits by disc 3. It's expensive and doesn't last long, though.