This is a really good place to stay in Old Montreal, and I would recommend it. Place was neat, cozy and in the core of Old Montreal with everything nearby, and there is a parking lot (Indigo) right behind the Sonder ($25/24hr).
Only issue we had was the construction right next door which started at 6 am on weekdays and 9 am on the weekends, which we weren't notified about before hand. The area does get quite noisy at night time but that's expected considering its a lively neighbourhood with lots of bars nearby.