I'll try and be succinct but also detailed for those interested. I stayed at Armin's place for a month in Oct-Nov 2020. A few points:
Location: Armin's place may look far out but it is only 15-20 mins to the centre by scooter, or 25 on public transport. Vienna is a small city and the location is totally fine for most trips to Vienna.
Facilities near by: There are several Billa supermarkets near to the apartment that have all the stuff you'd need to cook meals and survive.
The apartment: You can't see it in the pictures, but the shower has an attachment so that it can hang and be used like a normal shower. It wasn't clear in the pictures before I came, and I thought you'd have to hold the shower head above you as you showered, but the attachment means you don't which is great!
The flat has an unbelievable ambience. The lighting is amazing and the japanese mural on the wall is stunning. For reference, for those for whom it's not clear from the pictures- you enter the flat and on your right is the bathroom. In front is the main living room and kitchen, and on the left at the far end is the bedroom. The bed is super comfy, with big pillows, and has amazing LED lights along the floor to create a really cool atmosphere.
The piano is very well tuned so a great feature for any budding musicians.
For those wondering around the European/American distinction, the flat is on the first floor (meaning one above the ground).
As all quaint buildings do, the flat can make some noises but don't be alarmed. It's usually either the water boiler starting up, or something creaking due to the weather. I got used to it after 1 or 2 days so it's really no big deal.
The people living in the surrounding apartments were very friendly, and would commonly offer a "Hallo" if they saw you which was nice!
Armin himself was super helpful, and even booked my taxi to the airport for me which was much appreciated. He gave some great recommendations, and he was always very quick to reply to messages, and given I stayed there for so long I had some odd questions (like how does the washing machine work?! haha) but he always met them with enthusiasm and general helpfulness.
Also not clear from the pictures but the 'office' area in the corner of the room has a second shelf that can be pulled out to create a deeper desk on two levels- useful for those looking to work from home in this place. Overall the wifi was fine here, though I did experience the occasional issue. Nothing that made working impossible though.
Armin's flat is a serious one-of-a-kind stay in Vienna at a great price point. I really can't see anyone booking this regretting it. It's the kind of flat that makes AirBnB so great. It's so unique and truly a treat to stay in. I would highly recommend it to anyone.