I am going to throw two votes into this game.
DASMOS He led the mafia very well...and was one misfired hit away from defeating not only Beta Townies, but also Alpha Townies. The second day hit was against Uncle Bob and Shift Key, which both had roles, and the Mafia knew them, but had the wrong Earths...if they would of had the hits correct the game would have been 100% different.
At the same time, there was poor townie organization, because the two Earth idea was confusing, but the information was available for the Townies to have a VERY STRONG and solid alliance, but it never formulated.
Shift Key, finally got enough information to pull out a win for Alpha, and I believe he deserves major props for that.
But, I believe the second best played person that truly led to Alpha winning was: DAaaMan64. This Killer had some brilliant hits that crippled the Mafia in Alpha. He was able to get 2 Mafia Goons...and hit and killed Stevey as the Detective which prevented the Mafia of Beta to use Townie surveillance to find roles.
For that reason I am also throwing a vote for
DAaaMan64
Without him Alpha would not have won. And he was able to hide his role from the Mafia for a pretty good time.