Quote Originally Posted by Raistlin
A quick comparison:

Vincent:
Good, dark story. Fits in with the plot nicely. The "silent, dark, brooding" type which is very cliche but still everyone loves. His story is only developed at two distinct points in the game(one when you first talk to him in a flashback, two if you go see Lucrecia in the cave).
Absolutely useless in battle; he's up there with Aerith and Cait Sith. His limit breaks look cool, but their lack results make him one of the worst characters you could have in battle.

Cid:
Excellent, developed story with a very original character. Cid gave up his dream to save Shera, and seems quite less antagonizing towards Shera later in the game. Is it any wonder that 99% of FF7 fanfics have Cid marrying Shera? One of the most developed playable characters in the game, and one of the most original FF characters.
Excellent in battle. Very quick and strong in battle, he can still wield materia. His limit breaks are also very damaging, which only adds to his usefulness.

Verdict: Cid.

Now SIT YOUR ASSES DOWN AND DRINK YOUR GODDAMN TEA!!!
That pretty much says it all. A fair and concise comparison of the two characters, good work Raistlin. Pretty tough to argue against Cid after reading that. Not that I'm biased or anything (points to avatar)