The apartment is in a nice area and not far from the river Moldau. Also you can reach all the big sights by foot, we never really bought a train ticket. The room is good and has everything you need, except of a cupboard (it has been only two hangers and nothing to put clothes in). Like somebody mentioned before it can become very loud, although it is not on a main road.
Please consider that you have to pick up your keys from another place than the apt to get into it.