Honestly it depends on what Sanchez wants.
Man City are winning the league in May so that's a definite winner's medal if he goes there.
Plus there's the other cup competitions and being part of a historic team for this season.
Going forward the future is bright with a progressive manager.
Game time wise, he'll get his odd share of games but would have to displace Sterling/Sane on the wings or Aguero/Jesus in the middle assuming all fit. There is the possibility though that Aguero could always leave so that may benefit Sanchez in an individualistic way.
With Man Utd, he joins an iconic club and plays with a style and tenacity that the manager would want.
Trophy wise, Utd always wins something at some point or another (people forget all too quickly that Mourinho won 2 trophies last season + Van Gaal won one the season before = 3 trophies in the last two full seasons), so it shouldn't be thought of as if you don't go to City you can't win the league or Champions league with any other English team.
Game time wise, for me he starts every game when fit. Martial and Rashford ain't seeing him at all in terms of skill, experience and influence on the pitch especially in the big games. Lukaku is his only competition upfront as Ibra is pretty much done. Playing in the No. 10 role should have been either Miki, Mata or Pogba's role to secure, but Miki is on the outs, Mata is a squad player and Pogba plays wherever but generally behind alongside a defensive minded player to compensate his lack of tactical positioning. Lingard got the juice now for the position, but Alexis is still the better player.
