I think it comes down to personal preference on what style of forward you like to see.
I was always a big fan of Tevez' style of play and think he should be remembered as one of the best City signings ever on his ability. I'm not sure I agree that he was more skilful than Aguero though, I just think they had two very different styles of play.
Tevez was an imposing battler up front(perhaps showing he played on instinct), he could hold the ball up with challenges flying in and get City a foothold in a game no matter what was happening around him. He'd also pressure opposition defenders into making mistakes all by himself(Pep would have loved to have him in his prime). There was a tenacity and aggression to his game that I think was missed when he left the club. As others have said, he could take games by the scruff of the neck. When teams came to kick us off the pitch and make it difficult to get going, he was the one to make things happen. He was always good for a "thunderbastard" of a goal, out of the blue.
Aguero's game was more nuanced(perhaps showing he was more of a thinker), his movement off the ball was on another level and that's what he opted for most rather than hold up play. As I remember it, Aguero had the better linkup play and was more of a team player. As for skill, he could just as easily take on 3-4 defenders, riding challenges(deceptively strong some defenders described him) before getting a shot off or providing an assist. He had every type of finish in his locker and he was more of a big game player for me.
I think Aguero is the better striker but Tevez deserves more plaudits than he gets. That's not the same discussion as club legends, which I don't think you could class Tevez as. Putting aside the golfing story and the way he left, he always seemed to be about himself but that was fair enough to me. As long as they are giving their all when they do play, there's no issue with it. Great player all the same and pretty unique, there's not many players I can think of that you could compare him to.