Definitely went with the good ending. Even though Jason changes throughout the game, his hunger for violence is still directed toward killing the men who hurt his friends. He may seem out of control, but I think the mission where you interrogate Riley, beating the piss outta him, he realizes just what he has become: a monster. Siding with your friends was much more satisfying because of this I think.
Hand me the keys to this bike, lemme start it up. YEAHHH!! It's trials time baby!!