When you put shake off on a character that has a power that allows them to break away automatically i.e. Leap/Climb, Phasing or other SP's does shake off take effect? or do you have to roll for a break away?

From the Player's Guide:

Note that there are some tricky things with wording here.

L/C has you automatically break away, so that doesn't work.

Your break away is always successful against Galactus, so that does work,