In all honesty, I really like Blake, but I think she suits the California girl look more than Mischa, who definitely could suit the look of an upper east side princess. But its irrelevant now.
I will say though, that for however many people hated Marissa Cooper, I loved her! Sure, she made stupid mistakes, but I got what they wanted to do with the character. She was the girl who no matter how beautiful, rich, or privileged she was, could never be happy. And even as everything was stripped away from her, she could never find peace for more than a little while. Still wish she didn't die though, she was the best. And i was a huge Ryan Marissa fan.