The main advantage is a 5-minute walk to the center of Sofia. We came here in February 2020, but the heating was good, the batteries were at -10, we opened the window to ventilate and did not freeze in principle. It didn't smell clear what, some kind of dampness, stale, I suspect that mold is present in the walls, but we stayed there for only 2 nights before going to Bansko, so we endured, but if you want to stay longer in Sofia, take a better hotel. It was strange that there were no clothes hooks in the hallway, I had to stomp to the room in jackets and put them in the closet. But on the other hand, hot water pipes ran along the floor and the shoes dried very quickly on the warm tile. In general, in terms of heating, Bulgarians do not huddle and heat like in Siberia)) Not economical)
An interesting solution was in the bathroom - the toilet in the shower. opposite the faucet: well, that is, you can wash your hair while doing your toilet chores, for example)) And you need to put the toilet paper away, otherwise it will get wet.
The view from the window... In short, it's better not to look out of the window. It feels like the city was bombed and then spray-painted.
In general, Bulgaria was very disappointed. And not only the service. The appearance of the city, roads, lighting - problems everywhere. Yes, you can say that there is no money for landscaping, but is it possible to wash it? Otherwise, the historical center of the European capital looks like a suburb of Ryazan. It's sad.