I stayed with Jon for 10 weeks this summer, and I had a great time! Jon is very friendly and welcoming, and is committed to making the house a safe, clean, and friendly place for his guests.
The neighborhood felt safe (this is coming from a 20-something female) and quiet, but there are places to grab takeout and other things you might need nearby. Only negative I can think of was that the place is about a 15 minute walk away from the Metro, which I had to take every day to get to my internship. But once on the Metro, the ride in to city center goes pretty quickly.
The house was clean and well-furnished. I did a lot of cooking at home, and the kitchen is fully equipped and has a good amount of counter space. And the Safeway across the street is super convenient for picking up groceries. As I hope you can tell, I would definitely recommend staying at Jon's house!