An Englishman who has since moved across the pond to cover Major League Soccer, when I first experienced a live MLS game, one thing stood out to me more than anything else: the atmosphere in the stadium.
Unlike in England where rivals fans compete with one another to provide the fiercest support for their teams, in MLS, that same raucous, contested, sometimes violent feeling is not quite as present. The demographic of support is younger. More families are present. Soccer attracts a more cerebral fan than the tribal character of English support.
Someone who understands this difference better than many is Mikael Silvestre, who spent the majority of his career in the Premier League before moving to Portland in the latter stages of his career.