As the top two teams currently in the Premier League, Manchester United and Manchester City both have very solid All-Star teams. With this popularity comes a lot of doubt on whether or not teams can win with this level of talent.
Both teams have their own issues that factor into their seasons' performance and finish. For Manchester United, it comes in the form of not letting this much talent go to their head, a new keeper's transition to the EPL, staying healthy and consistency from their top players.
For Manchester City, the factors include finishing with a win in big games against big opponents, mending relationships between staff and players, keeping a level head throughout the whole season, making better decisions with management and the biggest factor is to improve consistency and finishing on top.