Both sides have done well to start the season but the fact that United are playing a better standard of football than they were last season, for me gives them the edge.
City / Guardiola will play the same possession - position - pressing type game against every team, home and away. This was their shortfall last season and even though they have improved the quality of the players on the team, they are still going to press high, keep the ball and potentially be vulnerable to the odd counter / park the bus type of games. None of that has to do with the players involved, but the tactics being instructed. Their next two away games vs West Brom and Chelsea will be a prime example of this.
United have changed the way they play this season and it suits the players now there. Last season, Jose played the wingers very deep and it meant that a lot of the attack went through Zlatan up the middle. I am not sure what has changed but the defenders are not being so protected by a deep midfield and, meaning the wingers and creative players can do their thing up the other end. What I most like is the confidence of the players.
There is a difference from last season, I am not sure how it came about, but everyone has it. I am not sure what has changed with City, other than the upgrading of the fullbacks and B.Silva in the attacking third.
One other thing that i want to mention, is that I am not sure how Guardiola is going to keep everyone in the squad happy. All are big name players and they do not have the squad players like United, who have the temperament to play when needed and just to do a job. Herrera, Mata, Blind, Darmian are all happy to rotate in and out,but i am not sure about Mangala, Sane, Toure, Danilo etc.
Unless one is actually in the squad it is all guess work how the other players will react to being rotated. Certainly don't believe all the crap I read. I am not sure that we should have a big turn over of players every game. You need a basic stability in the side and the fewer players you use the better they know each other. With so many games you have to rotate but the key to it is to know how many and when.
I hope that we are better than City but right now I would not bet my house on it.
Would rather be cautious than cocky like some supporters.