Poll
56%
44%
Tifa is an extremely well-trained fighter in addition to a capable materia-wielder, while Aerith (😛) is a flower girl who also happens to benefit from Materia use. Special abilities like Great Gospel do not directly translate in battles like this so I'm going to have to go on pure talent alone, mixed with a common sense interpretation of how the battle would go.
Tifa.
We are talking about realistic battles in the context of the game, not battling in terms of the game's mechanics. In a realistic battle, there are no limit break bars, there aren't 99 Megalixirs, and there aren't magic points. This is the comparison of two video game characters as expressed in a real-life situation. You can't determine things merely by the way that you play the game, otherwise the battle can be anything, like a Lv. 99 Tifa vs. Lv. 30 Aerith. In the real story of Final Fantasy 7, people aren't saying "Barret, use Fire 3 on Bizarro Sephiroth's left arm, then use a hi-potion on me after I cast big guard." All I'm saying is that video game comparisons are inherently meant to be expressed through real-world equivalents, and are not defined by the games' terminology alone. When people want to speak about which fighting game character is better to use, the situation is different, but the thread's author was obviously making this a realistic match.