The space is smaller than expected, but fits three guests just fine as long as you aren't messy. The bathroom is quite small, so it might not be suitable for very tall/large guests. The trains can be heard right outside the window, but this is not much of a problem if you
sleep a little late anyway. The curtains are a big deal since the building lights outside the window can be quite bright. Don't expect to do any cooking or eating in unless it's just chips or snacks.
The best parts about this apartment is that it's situated very well, and you don't need to keep a key to get in and out. It's a short walk to the station, there are several convenience stores nearby, and a small grocery as well. The key code made it easy for our group if we chose to separate while we were out and come home on our own, since we didn't have to rely on a key to get into the airbnb. We were also with another group who booked a unit on the same floor as us (same host), so that was also great that we could just convene in one room to hang out or plan our trip for the next day.
Our host is very quick to respond to all our questions, so don't hesitate to ask them for anything!