Tifa's limit breaks are weak, the only reason they're worth a damn is because she can use them all at once, but that's still not that great. Her weapons arn't that great either, and her feats are shit since she's just an addition for Cloud's character, and a plot device to break him from the Zackesk persona. I've played 7 four times, and seen AC twice...and remember, she got her ass handed to her on a platter in AC by some jackass Cloud owned later on. Shit, Vincent even held his own against all three for a good chunk of time. Even if you compare Tifa to the other characters in FF who are monk style hand to hand combat fighers, she's buried at the bottom of that totem pole.
Look, I like Tifa, I've used her twice in my play throughs, but she's 99% a add-on character for Cloud's entire persona and story, and the start of that trend that seems to have plagued the FF games that came after, sadly.