We loved staying at St Mary's - quiet and peaceful with awesome views. Easy walk to the Visitor Centre to catch the shuttle and enjoy the scenery with someone else driving, plus get on and off as we went all the way through. Saw lots of huge bears that came down every evening around dusk for the berries end August/early September = kept the rangers on their toes but wonderful to see them in their natural environment and up close.
If we were staying longer than just 3 days, we would have spent a further 3 days on the West side around Apgar or Fish Creek CG, just purely for the experience of having done both sides. If we were to stay again for 3 days we'd still stay at St Marys FWIW.