I'm one of those that falls on the unlocked framerate side. Give an option to lock at 30; cool. However, personally, I like Shadowfall and Second Son the way they are.
I don't see the fluctuations that some apparently do. As long as it's 30fps and above, I'm fine if it flows between 30 and 60. Only when it drops below 30 does it bug me, and it doesn't in those two games (except maybe once in a blue moon).