We stayed at Emil and Anastasia's apartment for 4 nights as a family of 6 in September 2015.
Their apartment is very nice, modern, and clean, and looks like the pictures.
It's located in a central location (Žitná street) such that we never had to use public transport.
I rate our experience 5/5.

Things to be aware of if you are staying there:
- We arrived late, so they left us the keys at a locker, so we didn't get to meet Emil/Anastasia personally (not your "typical" Airbnb experience), but they were very nice and responsive over Airbnb so that was not an issue at all.
- The entrance to the building isn't very "nice", but don't worry, the apartment is very nice :) After you get inside the building, walk straight for ~30 meters (don't open the gate on the right), then you will find a gate in the corner that leads to some stairs. Go two floors up, and look for the modern brown door. Use the small key for gates, and the big one for the apartment door.
- There's no elevator and there are ~50 stairs to get to the apartment, so keep that in mind if you can't carry your luggage. (In that case you could probably ask them for help before you arrive.)
- There were two Wi-Fi networks. One password is under the router and the other is on the map you get with the keys.
- The heat is central in the building, so it might not be on if you go there in September. Not a huge issue though.
- If someone in bedroom 3 wants to go to the bathroom/kitchen, they have to go through rooms 1+2. This wasn't an issue for us as a family, but for 3 couples it might be inconvenient...
- We found the washing+drying machine a bit confusing. Ask them for instructions if you plan to use it.

General Tips:
- We used to do shopping at Albert, which is a few minutes walk from the apartment.
- You can get to the apartment from the airport using Emil and Anastasia's own service, or use http://www.pragueairport.co.uk/taxi-from-to-prague-airport_to_centre/ - these guys provided us a free walking tour the next day, which was informative. We also emailed them to make a reservation for a ride back, which was convenient as we couldn't make phones calls in Prague as tourists.
- There are several close Vodafone stores around the area (see in Google maps). You can get a 1.5GB data only prepaid SIM card for 400 CZK = €15. This was very convenient. For more info consult http://prepaid-data-sim-card.wikia.com/wiki/Czech_Republic.