We stayed 4 weeks and everything was great! The host was super helpful. He gave us tips on getting from the airport and was waiting for us at the door to let us in and explain everything. I have not had a nicer host.
The apartment has a very convenient location. It is right next to the National Museum and the Wenceslas statue (Wenceslas Square is sort of Prague's version of the Champs-Elysees). The flat is literally around the corner from an entrance to one of Prague's main metro stops (and inside the stop is an Albert's supermarket and another shop with everything you will need). Tons of cafes, pubs and shops are also a short walk away. Prague's main train station is just about 3 blocks away.
The apartment is very typical of the type of apartment you find in Prague's many historic buildings. Wifi is great. It has a living area with 2 large windows that open to a courtyard, a TV, a large couch and small dining table. It has a kitchen with oven, stove, microwave, electric kettle, big refrigerator, and all the extra stuff you need for cooking and dining. It has a bathroom with a clothes washer (which is super helpful for long stays). The bedroom has a large window and 2 beds that can be put together if you wish.
We were there in August and the room stayed pleasantly cool the whole time.
Also, try the pub Moskyt on a side road about a block from the apartment (very cheap and friendly service).