Board Thread:Game Discussion/@comment-5977413-20130626142407/@comment-10976699-20130626163947

Also, factions only matter during events. Read the event description to see the bonuses for the event, which will usually encourage you to go with more Autobots/Decepticons. At the beginning, you will likely have a mixed deck with the top row being one faction or the other depending on the event bonus. As you get more R4 cards, you will eventually use either an all Autobot or all Decepticon deck for the event (usually after 3-4 events).

Check out the bonuses when you "Edit" in the "Team" screen. If you touch on the bonus icons a screen will pop up showing you all the potential bonuses. There is a hefty bonus for using a character's signature weapon.

The question about atk or def is tough. I usually try to just maximize my "deck power" number.