I've recently returned from staying in one of Dimitri's apartments and the booking was handled smoothly and efficiently by both Airbnb and Dimitri.
Dimitri has several apartments in the same building and I stayed in number 3 which is a ground floor flat with a small balcony to the street which has a table and chairs so you can sit out on a nice day. The apartment is quite small but fine for 1 or 2 people. It has a double bed in a part which is separated by double doors and a sofa bed in the living area. The bathroom and kitchen area are compact but have the essentials. At first glance, the apartment seemed quite clean although it could have done with a more thorough clean in not so obvious areas. The flat is a 20 minute metro ride to the modern part of downtown Montreal and about 30 minutes to the historical part or old port - it's the last stop on the green line of the metro. The area has everything you need though and is very safe - there is a big indoor shopping centre and supermarkets about a 10 minute walk away and a lovely park next to the metro which is also 10 minutes walk from the flat. About 7 minutes walk away there is also a free outdoor swimming pool and kids playground. The main drawback for me was the lack of noise insulation in the building - people walking above sound like they are coming through the ceiling, but if you are going to be out most of the time this shouldn't bother you too much and it was quiet at night. I did have some problems using the smartTV - you can only watch TV by internet - but again this didn't really worry me. Dimitri responded quickly to all my emails and kindly allowed me to leave my luggage in his studio on the last day as my flight was late in the day.
All in all it was good value for money in a nice area with good links to the city.