I've spent many nights in downtown Calgary hotels, and Best Western Plus downtown has become my go-to favorite. I've probably stayed there 70 or more nights in the past 12 months. It's aging a bit, but it's well maintained and clean.
The first thing I love is the staff. From the front desk to the housekeeping, everyone is friendly and work hard to ensure you have a great experience. It doesn't matter what hotel you choose, issues will occasionally arise, and at this hotel those issues are promptly resolved and the management and staff ensure you are completely satisfied.
The free breakfast is consistent and good. The in-room internet is available as both wireless and wired, and I've never had any issues with the internet connection (and I'm a heavy business user). The hotel is conveniently located close enough to downtown Calgary that you can easily walk, and only a couple of blocks from the activity of 17th Avenue (plenty of great restaurants and night clubs)
Great option if you need to be close to downtown, but don't want to pay the over priced downtown hotel rates.