Are you saying you only have 2 nights to spend in the Banff/Lake Louise area in total, or do you have more time and are just asking where to spend your free night certs in addition to some additional days?
To stay just one night at each place you are going to feel rushed. If you have only 2 days total, spend them all at one hotel to avoid the check-in/out and packing/unpacking each day.
I just finished 3 nights at the Springs in an upgraded river view room (used room upgrade) and 2 nights at the CLL in a Lakeview Junior Suite (used Suite Upgrade and Free Night certs). I think I liked the CLL best. On the other hand, my wife preferred the Springs. The Willow Stream Spa at BSH is great. I found the general repair condition of the CLL to be better than Banff.