I personally loved this place. Its in one of Paris' most ethnically diverse quarters and absolutely great to walk around and explore. Its not that closely located to many of the main tourist sights (with the exception of the Sacre Coeur/Monmatre, which is about 1.5 km away), but is a fantastic base to experience the 'real' Paris.
I didn't see much of the host or his flatmate, but both were very friendly and helpful.
The apartment itself was spotlessly clean and had good wifi. However, the photos do somewhat flatter to deceive, as the building is old and pretty shabby, the room is small and faces onto the main train line meaning its quite noisy (although Aureliano kindly provides earplugs), and you'd struggle to get up to the apartment on the 4th floor with a big suitcase.
Nevertheless, it has its own charm and is great value for money given Paris prices.
So, if you want somewhere close to the centre that is polished, new and roomy, you'd probably be better off looking elsewhere (and be willing to pay higher prices!). But if you want somewhere that is cheap, charming, full of character, with friendly hosts and you are interested in exploring Paris' rich cultural and ethnic diversity, this place is great! (Btw, the area on the other side of the train line has some of the best Indian food this side of Singapore!!!)