For me, no better choice than this very well-furnished apartment close everything in Warsaw. The Veturilo station (bike rental) is just 100 meters from there, which allows you to ride a bike throughout the city (you might have to wait until Spring for that, now...).
On the downside : the shower was not properly fixed, and this is something I had already mentioned after my second stay last Spring. Same thing for the light over the bed (but it is a first problem, here). Maybe a regular checkout of the apartment's equipment would be advisable, followed by the necessary repairs... mehr