I am with Big Heavy on the "not a fan of non-symetrical" shapes... so from the two choices I personally would go with the Faction. I have heard a lot of good things about the faction. they have a vest and a handle that are also named the faction that are usually stylized to match well together. AND there is even a team of riders that ride the Faction line that call themselves, well, the faction team of course. All this cant be said about the Vault that i know of
FYI i have not ridden either of these boards, but i have tried the hyperlite version of the Vault and i personally thought it was my least favorite ride yet.
And... as Eubanks (eubanks01) said, there will be other people who will recommend some other boards, I am sorta that kind of guy, but i always try to stay on topic (not completely disregard it) of the original question as i have done above. ;)
and my recommendation is a Slingshot Recoil. and there happens to be a limited time (today only) closeout on it on this site here --> http://www.boardersbestbuy.com/
Slingshot is the innovators of the flex-board technology that has recently begun to really turn heads in the wake industry. Super soft landings and responsive pop. Super fun to ride both on the water and in the air. Good for beginners all the way to experts, in my opinion.
it comes with really nice comfy heat-formed bindings as well.