My preference is the Science starter. I think that a science group will do well in the game but there is always the threat of battle. So I think the goal is to have a well balanced team, one that lets you research but is also able to protect itself.
For some reason I do not see a pure science team doing well if there is any kind of physical treat on the new planet.
As for Factions, I am unsure what direction to go, as not enough details and game play have been released yet. Really looking forward to the Factions game play and seeing some of the cards in action!!