All my characters in all my groups have the exact same keybinds. Moreover, in each group, the same types of actions are always set at the same place, i.e. the mean DPS macro is always on the same key, the "pull" macro is always on the same key, main heals are always on the same key, etc ... This all makes switching characters really easy.

For instance, I am currently using my PVE group (Pala + 4 x Shaman) to run the hunters from my PVP group (Druid + 4 x Hunter) through Heroic Utgarde Keep (for the epic crossbow, still two to go). I just swap one Shaman for one Hunter. All it take is defining the new group in Jamba, press "Push to characters", and off we go !