So I finally broke down about a week ago and built my first Lanny LCG deck, primarily with the purpose of proving it is not "far and away better" than the other houses like some have claimed on this board.
So what I found disturbed me. The deck has dominated. It has lost twice, but both losses were in the first 5 games it played, and were due to bad location draws while playing against a Winter deck. After a few modifications (adding Weaponsmiths) and some familiarity while playing it, it hasn't lost since. Not only has it not lost, it hasn't really had a close game.
Thus first, I offer a retraction. In some of the other threads I stated that while I thought Lannister was the best house, I didn't think it was as dominant as some had stated. I retract that and say that I now think that it is not only best, it is clearly head and shoulders above the rest. Prior to building the deck myself, I had played fairly evenly with my Targ deck against Kennon's Lanny. But things have changed.
Second, I will say this. I think there are really two primary cards that create this significant increase in power level: Castellan of the Rock and Golden Tooth Mines. As an opponent to Lannister, if you can find a way to immediately and repeatedly remove these cards from the table, you will probably find your road to having an even battle against Lannister.
Third, I just can't see myself playing Lannister at Gencon. I'm too much of a contrarion. So now I'm off to make my deck that I think can somehow hold its own against the wealth of Lannister LCG decks I expect to see.