I would absolutely stay at Mo's place again. The studio is just as described - it's wonderful, very convenient, and perfect for one person. It has everything you need and, given the nightly rate, blows any hostel or budget hotel out of the water in terms of cleanliness, privacy, and quality of the amenities. I've stayed at a lot of other AirBNBs before and I think you can tell when a host is doing it because they actually enjoy it or when it's just a money grab for them. Mo definitely cares about the guest's experience and is very helpful in getting you oriented to London and Willesden (the neighborhood). It's close to lots of local restaurants, pubs, and grocery stores, as well as to the Willesden Green stop on the Jubilee Line. It's about an eight minute walk to the station and then about a 15-25 ride into Central London, depending on where you are going. There are also a number of bus routes that go through Willesden.
In terms of food in the area: I'd recommend the Turkish restaurant called Lezziz Charcoal Grill (also recommended by Mo) - they are very meat forward, but have a great vegetarian platter. I'd also recommend the Queensbury for a pretty decent pub and the Spoon and Rice Filipino restaurant. All are within a 10-15 minute walk of the studio. Sainsbury and some local grocery stores are also in the area.
Helpful tip is if you are going to Heathrow early in the morning before the tube is open: you can catch the N266 bus across the street from the Willesden Green station and take that bus directly to Acton Main Line Station to catch the new Elizabeth Line..saves a lot of money and time because you don't have to go into Central London to then backtrack west toward Heathrow.