We stayed at Bears Den for 5 nights in July, and had a great time.
Field is a great base in the Canadian Rockies as it is very close to a huge number of very different sites in both Yoho and Banff National Parks (e.g., Emerald Lake, Lake Louise, the Iceline Trail). It is a small village, with 2 restaurants, a general store and post office, train line and a couple of hundred people - very quaint, and a very different feel to the Disneyland toy town of Banff and the "I'm not really a town" of Lake Louise.
The accommodation at Bears Den was perfect for us: 1 double room, 1 twin room and 1 comfortable large sofa bed, along with a large kitchen. It was spacious and clean.
However, what made our stay brilliant was the warmth and advice of Lorraine: she works in the National Park and knows EVERYTHING, helping us to plan every day with a huge smile and directing us to highlights in the national parks we certainly wouldn't have thought of going to without her!
Brilliant stay; highly recommended.