Quiet street near a park, walking distance to Old Town Square (about 15 minute walk). Apartment was clean and exactly as described - it seemed newly remodeled and I think we were the first guests to stay in it, hence the lack of reviews. I'm glad we took the chance on it.
Host company is responsive and welcoming - we were even given a map of Prague on check in. The office is right outside a Tram 22 stop, though we drove there to get the keys. While I would prefer a lock-box key pick-up or being met at the place, our check-in was very smooth and they were responsive and flexible for our arrival time.
Note that there are parking garages and a free lot within walking distance (we parked ~10 minute walk away in a garage) but be warned that parking in Prague especially Old Town can get crowded and full on weekends.