Just great :)
We vere driving and checking in really late (at 11pm), and Peter and his son Jack had no problem with that - they provided us with the detailed information of how to get to apartment and how to obtain keys.
There's a parking lot right next to building, you can find a place there, if you're lucky. We were :) Anyway, it's not free, it costs 30 CZK per hour on Mo-Fri from 8am to 8 pm (or to 10pm, don't remember actually :/) - price is ok, as for me.
Location is great, you can get to historical center in 15 minutes walk, to the Dancing House - in 5-6 minutes walk over the bridge. There's a big mall in 2-3 minutes walk (on next street) with everything you may want to buy ) and the tram stop right in front of it. We didn't use public transport, though, as everything you may want to visit is in walking distance.
The apartment is just awesome :) It looks great on photos, but it looks amazing in real. It's actually a two-level apartment under the roof, it's clean, it's spacious, it's the place where you want to stay for a while :) And the kitchen is big)
Peter's son, Jack, lives next door, he is super-friendly and was there to help us with all our questions or problems we could experience during our stay.
And in the evening we enjoyed a couple jars of beer in two pubs right across the street in the park, with a very tasty beer that costs almost twice less than in center :) - another plus to a location.
The result is - we would definitely look to stay at this apartment again next time when we come to Prague.