Yeah the event was fun and rewarding.

From what I've learned, for the PvP event you need to level up only a small amount of cards (5 or 7 if you also use a trap deck in defence), that you will use. Each of your cards will fight vs one of your adversary the one who get 3 wins, win the fight.
The thing is Moe is strong against Sexy, Sexy against Babe and Babe against Moe. A card which is strong against another will have it SED x3.
If you set up 3 card of a same attribute in a deck you will be labelled as of this attribute. Someone who is searching for an adversary will see their attribute before attacking.

I'll personally go for a 4 Moe 1 Sexy for offense and 3 Moe 2 Sexy for defence.
My source is the JP PeroPero wiki ... with google translator so it's sometime hard to understand. (Well I understand Japanese but can't read it, so when google mess up, I have to listen to the JP sentence to actually understand anything, it can take quite long sometimes.)

And to answer Xanthius : yeah she was the normal Akie, and yeah it was not the most useful reward. xD