Pros: the bedroom is large enough to have real private space, with a small fridge and a good bed. Flat location is great, as the old city center is about 10-15min walks, the castle is easily accessible thanks to public transport as well as the main train and bus stations. There is a good café (Costa coffee) in front of the building which allows you to have a nice breakfast (unfortunately not opened on saturdays/sundays/holidays)
Cons: very noisy as the flat is in a busy street, with a lot of ambulances and police cars. Not a lot of electrical outlets inside the room, you may want to bring an electrical power strips if you need to have more.
General: good quality/price ratio, really enough to discover Prag for a few days!