Which user base has the most skilled gamers Sony, Nintendo or Microsoft?

[DirtyP2002]

Well if you go for esports, Xbox 360 is basically the only platform. (WCG, SEC, ESWC)

Check gamebattles.com for a reference.
Even in Germany, a Sony-Land, the biggest eSports-website for consoles are played on 360 first. And even for games like Dead or Alive.