There was much discussion over how the shortcut for the Pen tool - the G key - should work in CS6. Adobe wanted it to work for switching between the Pen tool and the variable mask feather tool. Knowing that some users might prefer the G key to toggle thru all the Pen tools, they made this a Preference. 

Open Preferences > General Preference and toggle OFF the option for "Pen tool shortcut toggles between Pen and Mask Feather tools"

However, they also fixed a big problem with mask editing. Previously, after you drew a mask with the Pen tool, if you selected a point it deleted it! In CS6, going back to an existing point gives you the Selection tool, so you can move a point easily. So now, you may not need to switch between the other tools just to avoid this problem - you should be able to do everything using just the Pen tool, and use simple shortcuts to switch to other tools.  On Mac, when editing a Mask with the Pen tool:

press Command when over a point to get the Delete Vertex tool

press Option when over a point to get the Convert Vertex tool  (you may need to use Command-Option officially as Mac uses the Option key )

and just click anywhere along a mask outline to get the Add Vertex tool

By using these shortcuts and using the default Preference (toggle is ON), you can then use G exclusively for switching quickly between the vertex editing and Mask Feather editing. 

cheers, Trish