I have always found All-Star teams intriguing in the sense that how does one expect to put together tons of talent from across the league, give them a day or so to work together, and then expect them to be a great team. It just doesn't quite gel (this is where those who really believe in team chemistry rejoice). The problem is that there aren't many sports that this can be proven in because you have to assemble a team of all-stars that are close in talent to a team for another league. For example, MLB All-Stars against teams in Japan is not a fair assessment because the play level is completely different. You can't take an MLB team and play them against MLB All-Stars because players should be on both teams.
However, for those of us who are interested in this really bizarre and unimportant topic, there is a league who has to rely on this: MLS. Because of the MLS development, there is not enough All-Star talent yet to field two teams in the MLB so they decide to do something much more interesting, bring in a big name team (For the record, they can do tradtional East West games, but it is not as interesting). This year it was Manchester United. While the players in the EPL (English Premier League) are better than those in the MLS, the MLS All-Stars should be on par with Manchester United. So here the difference is how the team works.
MLS has used this system since 2003 till now (with the exception of 2004) and in each of those games so far, the All-Stars have lost. Its starting to be clear that either our All-Stars suck, or their really is something to concept of a team. Just food for thought I guess.