The place is spacious, and the service is good (you can see the servers are professional and courteous), otherwise it would get a 2-star rating.
We went to Yellow Door for brunch and I cannot say I enjoyed any part of it.
The buffet has very limited choices, and the egg benedict simply smelled bad.
If you are going for a buffet brunch in downtown Calgary, there are lots of other choices for the same price. Not going back.