We stayed for three nights in Jakub's place in October and enjoyed it very much.
The appartment is great, the area where its located amazing. Metro, trams, old city, Charles' bridge and the castle are super easy and fast to reach. There are plenty of places to eat and dine out, have drinks and enjoy the city. The main central station is also quite close and can be reached within a 10 minute walk.
Overall, for a stay in Prague this place is very convenient and comfortable as you never have to long travel times or any other negative impacts to your trip.
When we arrived, Andre, one of the co-hosts, was already there to great us and let us in. We did not have to wait or call or anything - super smooth and relaxed arrival.
Should this appartment be available the next time we visit Prague, we definitely will stay there again.