For a 3 star place, you couldn't possibly ask for anything more.
While I definitely wasn't looking to stay at the Ritz Carlton I did need to a hotel that was clean, comfortable, and offered a great location at a reasonable price. We stayed during the week before labor day and paid less than $100 a night.
I can't stress how great of a location this is. It's right by UQAM (what seems like a fairly large university) in the Latin Quarter so there are a lot of young people in the area - which also means a lot of fun bars and restaurants. It was really convenient both in the morning (when you're starved and need to get something before you make the trek to wherever you're sightseeing) and at night (when you really don't want to walk too far just to grab a cold one). It is also located about a block from one of the metro hubs where you can pretty much jump on any of the different lines.
The room we stayed in had one queen. It was a pretty comfortable size for two people. It was also very well kept - a little outdated, but spotless with a very comfy bed.
While we didn't interact too much with the employees, they always greeted us in a friendly manner and helped out with whatever few questions we had.
Note: It seems the most "tourist-y" part of Montreal is the Old Montreal area. That may be better for families, but I think this area is much more convenient and interesting to couples/friends traveling together. If you do stay in the Latin Quarter, definitely choose the Hotel St. Denis.