I stayed at the Fairmont Banff Springs Hotel in April for a quick birthday trip.
My wife and I stayed in Room 869 which had a mountain view. I read the reviews that said that the rooms at the hotel were small but I found the room to be actually quite nice and a decent size. The bed was really comfortable which I was surprised by as most hotels usually have "middle of the road" beds.
The hotel itself is incredible. Although the stores and spa in the hotel can be a little pricey, the experience of staying at a piece of history makes up for it. Our group spent a lot of time at the outdoor heated pool and the indoor "grotto" hot tub which was quite relaxing. The patio with the view is also amazing.
We had dinner at the Waldhaus restaurant which was really good. We also hit the Waldhaus pub the night before. I found the restaurant and pub staff to be really friendly.
I would highly recommend this hotel to other travellers.