Another non-Mariott option is Canmore, about 25 minute drive from Banff. The Pocaterra Inn and Waterslide is excellent, though you wouldn't think so. It used to be a Best Western I think but it's unbranded now. I've only stayed there once a few years ago but it's really beautiful and the hotel was absolutely on par with any Marriott I've stayed in before (closest I can describe it as is upscale Courtyard, the newer style, but more appropriate mountain decor).