The place is exactly as described and Sebastian and Marcela were very communicative and helpful. Marcela met us when we arrived, and gave us a lovely mini tour of the apartment and left us with tasty treats that are local to Prague.
The location is perfect, right next to the trams and a subway station. There's a grocery store, coffee shop, and bar/restaurant all in the same block. You're also in walking distance to Prague Castle, and a beautiful park nearby if you're feeling like walking around town - which we did! We made it to the heart of the old town, the Charles bridge, museums, and a lot of great bars and restaurants close by.
I would definitely stay here again, and I highly recommend you stay here if you're visiting Prague.