If you go to the site, you'll see a list of the top NBA players ranked by an adjusted plus/minus stat. This stat should at least theoretically be better than PER since it captures the defensive performance of the player as well. There is noise, since the performance varies based on the players teamates and who he is matched up with.
At any rate by their ranking, the best NBA player by far is LeBron James. Second is Mr. Iguodala and Third is Chris Paul. followed by Wade, Garnett, Nash, Foy, Rashard Lewis, LaMarcus Aldridge and Russel Westbrook.
It seems that Iguodala deserves to be in the all star game after all. Frankly, until I became aware of this stat I didn't think he was entitled based on his early season performance. Lately, since Brand got injured, Andre has taken his game to a higher level, but I didn't think it would show up on any objective measure.
Based on PER there are other players who's stats look better, but when you add in defense, which IMO, is a huge part of the game (just ask Pops and Bruce Bown!) it shows who really plays a good all-around game.
Since this is a new type of stat, it doesn't have a long-term track record, but it does appear to be fairly accurate, as the top players on the list are top players in the league, with a few changes. The problem with all-star selections is that everyone is scoring oriented. Who ever puts up the most points is the player they select. But some guys take too many shots to make their points, which hurts their team. People don't consider shooting percentage very well. This stat takes everything into account in terms of actual results.
The site is pretty cool for stat geeks.