We would highly recommend 77-St.Vallier! The location was perfect - a 15 minute walk (if you walk fast) to all the sights of Old Quebec. Lots of coffee shops and restaurants nearby as well.
The apartment is very well laid out and has everything you need. Super clean and comfortable. We loved having windows we could open! At night though if you close them, it is super quiet!
Having a parking lot you could park in all day ($18CDN) was helpful, as we wanted to walk to everything and avoid driving.
Hosts are very friendly, accommodating and available to help answer any questions!