Good. Like last week, one notch below the top grade. Definitely entertaining and interesting. The realization of the far out setting was fantastic. Top notch for creativity. However, the resolution was weak, very weak. I suppose it was trying to build the mystery surrounding Clara, but't it's got to stand on it's own. It fell short there.
So, was the reference to Susan (unless he has other Grandaughters), a throwaway line or is it of importance? Where did the Doctor vanish to? Was he off on another adventure? If we were supposed to gather some mysteriouness from the Doctor's visits to Amy's past, I missed it other than just seeing the importance of the leaf.