So my gaming group (5 and maybe couple guys more) intends to get into this game. We want each of us to be able to play his own faction without ever feeling restricted by lack of cards. So how many times do I need to buy what (including expansions, boxed sets or whatevs - This is totally new to us, so please elaborate if you please).

A second question comes to mind as I typed the first one. Is it a well balanced game or are we all gonna play 2-3 factions after we get a bit into the game ?

So my gaming group (5 and maybe couple guys more) intends to get into this game. We want each of us to be able to play his own faction without ever feeling restricted by lack of cards. So how many times do I need to buy what (including expansions, boxed sets or whatevs - This is totally new to us, so please elaborate if you please).

A second question comes to mind as I typed the first one. Is it a well balanced game or are we all gonna play 2-3 factions after we get a bit into the game ?

1) If you want to be totally unrestricted in building decks, then each of you should own three core sets and one of each expansion (at the time of writing, only Taking The Black and Road to Winterfell).

2) It's a fairly well balanced game but expect to see multiple people wanting to play Lannister and Targaryen.

out of the core set box Brath and Greyjoy are really overpowering to the other houses. Kneeling and stealth can be really hard to stop/come back from. Either way its a fun game. Now it really depends on IF your group is fine with playing 1 house maybe 2 for some if your good at 1 or 2 houses per player (keep in mind there are only 8) then 3 cores for the group should do the trick (keeping the neutrals at 2 each per house deck) otherwise 3 cores per player would be best. As for chap packs 1-2 for the group share or if everyone wants a chance at all houses then 1-2 each player...

out of the core set box Brath and Greyjoy are really overpowering to the other houses. Kneeling and stealth can be really hard to stop/come back from. Either way its a fun game. Now it really depends on IF your group is fine with playing 1 house maybe 2 for some if your good at 1 or 2 houses per player (keep in mind there are only 8) then 3 cores for the group should do the trick (keeping the neutrals at 2 each per house deck) otherwise 3 cores per player would be best. As for chap packs 1-2 for the group share or if everyone wants a chance at all houses then 1-2 each player...

Really, since the Targ deck the core shaped has hardly gained any new cards and is still doing amazingly in the tournament scene, and Lannister (especially Lanni/Rose) has been doing amazingly as well... I think this "2 overpowering decks in the core" is disingenuous. I will say that Baratheon and Greyjoy are the simplest to build and play, as the pieces 'click' together rather obviously to build strong decks. If you play the "melee" (>2 player) version you'll find other houses rise to prominence as well.

The posters above are right, if you want to feel "completely" unrestrained in deckbuiling, and have every player have every possibly option - yeah, you're going to need 3 Cores per person, and 1 chapter pack (of which there are 2 released to date) per person. But realistically, that's not where I'd start (and probably not where I'd end, if people are willing to swap cards/draft factions, etc - you can cut that number down drastically). If you're 5 players regularly and you want to see if you have a taste for the game, start with 3 cores, and see how you feel about it. It might be that some players will gravitate to certain factions, or that you guys will want to add an aspect of "Drafting" the factions (so that no more than 2 players can pay it) etc, to add variety to your games and reduce your overall costs significantly.

So - here's a related question: Are the products from the first edition compatible with the second edition? or is the second edition a new starting point?

They are not compatible - card backs are different, to start with. Some concepts and terminology have changed between editions, and costs are pretty different.

The new 2nd edition core set includes all 8 factions. In 1st edition, the core only included 4 factions and you had to buy expansions to add the other 4.

Although the new box has 8 factions, it only includes enough cards for 4-player games. If you buy a 2nd core box you can have enough for 8-player games, but you will be a little light on economy cards.

I've got two cores, and last night I decided it was just too little and ordered my third. With just two cores I have about 33 character cards per house, which means I basically just lump the whole lot in for a monofaction deck, with no variation. Boring! With 50% more I can pick 30-35 that fit better together (i.e. 3x of the solid ones I always need), and fill the rest of the deck with locations, events and attachments with solid draw.

The third core means I can have some common economy/neutral cards in several decks at once. I find that less hassle the way I sleeve my decks (thematic art sleeves for each).