Great apartment, spacious, very clean, lots of towels to exchange them, lots of cutlery and dishes, big kitchen with big fridge and freezer, no issues with the hot water.
Erich was very patient and waited for us as we arrived later than expected, thanks again for that.
The apartment looks exactly like in the pictures. Quiet building.
A few meters away on the same side there's a supermarket with everything one might need (pretty big SPAR). Metro station Musemsquartier a few steps away (literally), just note currently the stations connecting Karlsplatz (the Opera station) are closed due to some work - there's a replacement tramway, 2Z, for when having luggage. We left to the Hauptbahnhof with bus 13A from Neubaugasse street , station is in front of Palmers shop, ride takes 20 mins.
Location is really close to everything - Mariahilferstrasse begings a few meters away, in diagonal you have Museums Quartier, on other side of the intersection the old musems (Kunsthistorisches and natural history), Opera and Kartner strasse (so the touristy old town including Albertina museum and St Stephan dome etc ) are around 10 mins walk, same is the famous Art Nouveau museum with the golden dome (Secession). From there a realy interesting street begins, Linke Wienzeile, with an 'island' in the middle between the 2 lanes of the street, full of really good restaurants with a great vacation vibe. Also you'll find a middle east spices area and other specialties. At the Kettenbruckengasse metro station there are 2 of the most famous Art Nouveau decorated buildings of Otto Wagner, really a must see.
All in all, great stay.