I live in Toronto Canada and from my experience (my job is touring around in a band, so I watch games all over the world, and have all over America and Canada) people tend to usually follow the obvious.. Arsenal, United & Liverpool. I have met City fans in Toronto ONCE. I was at a Toronto BLUE Jays game and some dude sat down in front of us with a city shirt (just my luck that I happened to have on a red polo shirt that night.. fuck) so I started yelling at him. He thought I was a united supporter taunting him. We chatted for 20 minutes. You never meet City fans. It's weird. I know they are out there, but its rare over here. The only other time I was ever approached after a game a few years ago (that we surely lost) I was wearing a jersey standing on the corner and an old man with no teeth with the thickest manc accent I have heard outside of the UK screamed "City" in my face and walked off.
My good friends all supported United about 5-6 years when we all started following the game religiously. City was my team, and I would sit there having to hear bullshit and comment after comment and have usually (although not always!) have to deal with their crap when the rags beat us. They aren't talking as big of a game these days, thats for fucking sure!!!!!!!
Although I have a connection to Manchester in my family (crazy long time fans who have a turnstile from old maine road on their front lawn and paint it blue every spring) I would welcome any new city supporter with no ties to anything. A few of my friends are new to football, and have chosen City. Love it.
That being said.. when an American with no ties to England chooses a team like Arsenal, United or Liverpool.. just because they are big clubs.. with good records.. the safest choices (maybe not so much with liverpool now a days).. it makes me fucking sick. I am still picking pieces of barf out of the back of my throat from the 3-0 loss to gooners this season.. GOD DAMMIT