In my experience of staying in dozens and dozens of Airbnb properties, there are two types of units. The first is used as an investment property and is professionally managed like much like a hotel. Immaculately cleaned, no personal belongings, fresh towels, basic essentials provided (e.g. coffee pods, a bottle of water, small shampoo/soap, etc). The second type is someone's home and they are renting it out periodically while they are out of town. Armin's unit falls into that second category.
While the unit was in a nice location, Armin was easy to communicate with and check-in/check-out went smoothly, it was clearly a unit that is his primary residence. Personal belongings were abound, his toiletries lined the bathroom, personal notes/calendar on the refrigerator, etc. Not that any of that is bad, but for me, it has the uncomfortable vibe that I'm crashing over at some guys house that I don't know instead of staying in a hotel.
Of course, this alone isn't worth a 2-star review, however, when paired with the cleanliness of the unit, it was. Frankly, I'm not entirely convinced that the unit was professionally cleaned at all. There was items in the dishwasher, the bed was made, but clearly not by a professional cleaning crew (actually, to be fair, it looked similar to the bed in his Airbnb listing images) and surfaces in the kitchen, bathroom, etc just seemed quickly wiped down, not cleaned/sanitized. Additionally, the bath towels were old and tattered and there was mold lining the bottom of the shower curtain. So, for me, the combination of the "sleeping in someone's apartment" vibe AND not feeling the apartment was properly cleaned (or perhaps cleaned at all) made this probably my most disappointing Airbnb experiences in 15 years of renting.
I paid twice what it would have cost to stay a block away in the Holiday Inn Express and I probably would have been 100% less freaked out by the experience. So while there were good and bad aspects of this rental, it wasn't for me.