Our visit was brief, we only stayed for a single night.
First the good stuff. Jean, as a host, is open to communication, polite, his response time is very fast, there weren't any problems regarding this aspect of our visit. Location is relatively good, it is not very far from Montjuic, it is around 20-30 minutes away from La Rambla and other nearby sights, there is a metro station very close to the apartment itself so you can easily travel. There are stores and bakeries nearby as well.
Now the bad stuff. First, the description is very vague and there is no notion whatsoever that this apartment is shared - there is a bedroom upstairs and a bedroom downstairs, there is only one bathroom that is shared among 4-6 people, depending on whether Jean is staying at the apartment as well (in our case one bathroom was shared among 6 people). Our bedroom was somewhat claustrophobic, there is a window that has a view on water pipes/pump so you can get some air, but all in all the room itself has a very poor air ventilation. The furniture in the room is simple, the bed was relatively comfortable. The bathroom has a poor drainage, so be prepared to clean the excess water with a mop. The biggest drawback is the cleanliness of the flat, there were aluminum foils in the drawers (serving what purpose exactly is unknown), the linen wasn't particularly clean, and the towels we got were freshly washed and not dried (better to carry your own towel if you can).
All in all, even though we spent only one night at Jean's place, we didn't have the nicest experience. We felt as thought we had no privacy whatsoever, and we weren't really prepared for that. In my opinion, the price should at least be two times lower and the description of the place should be a lot clearer.