As I understand it (still waiting for the postman) the Core Set contains enough to form a deck for Stark, Lannister, Targ, or Barratheon, but only a fairly basic one.
Kings of the Sea contains 60 cards, mostly Greyjoy. Princes of the Sun provides a similar number of cards for Martell, but two copies of each of them.
If I've got anything wrong so far, please correct me, otherwise i'll be working things out based on false information.
What I'm wondering is - if I pitched a Greyjoy deck from 1x Kings of the Sea, or a Martell deck from 1xPrinces of the Sun against one of the initial 4 houses from a single Core set, how would they compare for power? would one be massively under or overpowered?
If there is a big discrepancy, I'm sure there's plenty of ways of correcting it with Chapter packs, just trying to get an idea of starting levels.