Recently stayed here for one night before an early afternoon flight out of YUL. The hotel itself is easy to find from the airport terminal and extremely convenient, as you literally just go down a few sets of escalators to get to the departure level. My rate was about $250 USD, so a bit high, but the convenience is hard to beat compared to the other Marriott properties in the area.

I used a NUA and got upgraded to the Premier Suite which came with concierge lounge access (they don't call it an M Lounge, which I found interesting - and you do already get access to this as Platinum Elite+) and a beautiful 700 sq ft+ room with wraparound ceiling to floor windows. Some areas of the room had clearly been renovated, but the bathroom was a bit old - tub shower with great water pressure, and it was clean and spacious, but just looks a little dated. The bathroom was also huge, but only had 1 vanity/sink. Another disappointment is that the "suite" isn't actually a suite with a separated living room - it's just one big open area with a divider wall that has the TV mounted on it.

Unfortunately, we ran into a few major issues that disrupted our stay:

• Our room's AC was extraordinarily slow - as in, it took ~20 minutes to go up 1 degree Fahrenheit. When we arrived, the thermostat was set to 62, so we quickly moved it up to 70+, and it didn't change for a good 15 minutes. We also felt cold air continuously pumping from the vents, so we called the front desk and they sent over a maintenance person right away. The maintenance person informed us that the thermostat is working, just extremely slowly. After a few hours, the room did eventually get to ~68 degrees, which was nice for sleeping. However, overnight, the room ended up getting too hot (even though we set the thermostat to 68) - when we woke up in the morning, it was 72. Soooo I think the AC was just broken in that room...we could've asked for a different room at that time, but we were very tired and just wanted to sleep and prep for our flight the next day.
• We were woken up by the large glass windows making loud popping sounds due to the direct heat from the sunlight right around 7 AM. Guessing this has something to do with the heat contracting the glass, but it feels ridiculous that this hotel hasn't dealt with this. Definitely a rude awakening, and didn't manage to get much sleep at all after we were woken up by the sound. Not sure if others have dealt with something similar or if it's just the layout of the suite I had, but it was something I've never had to deal with at any other hotel with large glass windows, so I was very surprised and annoyed.

Overall, if the AC had worked and we hadn't had a sunny morning, I would've loved the hotel! Hard product is decent, rooms are quiet, and it's close to the terminal - exactly what you ask for when you book one of these hotels. The concierge lounge breakfast was fairly good for how small the lounge was, and there was even an attendant that worked diligently to clear plates and put out new food, etc.