The apartment is in a great location for seeing the sights. Literally one block from Albertina, St Augustine church, and Spanish horses; two blocks from Hapsburg palace complex; and 3 blocks from St Stephens cathedral. Plenty of food options nearby, including the original Sacher torte in Hotel Sacher.
The apartment is on the third floor with no AC so you need to keep the windows open to keep it cool. At that height there's a nice breeze to keep the apartment cool, but the trade-off is street noise. This is a mixed bag. It was charming to hear faint organ music, opera singing, and church bells. It was less charming to hear people talking in the street below late at night or hear the church bells ringing wildly at 7am on weekdays. I think the pros offset the cons but just a warning in case you're a light sleeper.
The host could be more helpful. For example, there was no guidebook so we had to proactively ask for information about check in and check out. The host did not provide clear guidance on how to use the wifi -- in fact she provided the wrong passcode and when I messaged her to confirm the wifi network name and password she was quite rude, saying "I sent it to you already." It also would have been helpful if someone had showed us how to use the key to the apartment because the lock is tricky. Providing written instructions about the wifi and door or how to use the washer would require little effort by the host but would make a huge difference for the guest. That said, the host was usually quick with her responses and the apartment was clean, ready on time, and matched the description so all in all it was a great visit and I highly recommend the apartment.