I've always thought bringing in skillful players from foreign countries into English Premier League (especially South Americans) slows down their game,makes them adopt to different kinds of playing style which eventually takes away their strengths.
There aren't many successful South Americans in the Premiership, but Tevez and Mascherano are both strong, tough, physical players and I think they'll do well.
Forlan couldn't settle in the Prem, Crespo didn't match his Italian form for Chelsea...I can only think of two South Americans in recent history that have done well here; Gabi Heinze and Gilberto Silva.
Hey, Illuminattile what made you put Vidic's picture in your avatar? I'm curious...
Btw, it's true that South Americans play better in other leagues. Just take Forlan foe example...