The apartment is absolutely charming. As others have mentioned, it is not as close to U4 Pilgramgasse as the listing leads one to assume, though this was certainly not a problem for me. There are several small cares one has to take (keys that only turn in a very specific way, etc), but (1) this is normal with old apartments and (2) the owners were absolutely clear and precise about all infos. I was completely satisfied, and highly recommend this apartment.