Rating depends on the league you're in. The higher the league, the higher the ratio of wins to losses you need to equilibrate at 0.
Higher league = more rating lost per loss.
And Lex, I believe the top 10 decks are *2 for ranks 8 - 4, *6 for rank 3, * 8 for rank 2, and * 10 for rank 1, but I'm not sure if those are accurate.