While they were polite hosts in person, I did have some issues with my stay. First, there are numerous other guests staying in this apartment - it is not just you and the hosts - and there is no lock on your bedroom door. So I did feel uncomfortable (and in fact, one of the other guests walked into my room at night, mistaking it for the kitchen).
Second, I received a message from the hosts, after I had already left for work for the day, informing me that someone would be entering my room in a matter of hours to service the boiler. Boiler service is a routine thing, not an emergency, so it should be scheduled for a day when you have no guests booked. They did not ask permission. Now, when I pushed back and reminded them this was against Airbnb rules, they did offer to reschedule for the following day - but I had the room booked for the following day too, so it's still not really appropriate.
Finally, I ended up leaving the Airbnb early. I had prepaid and was ofc not requesting any money back. But the host repeatedly messaged me, being very pushy, trying to force me to cancel my booking so that he could re-book it- while still keeping my money and therefore get paid double. I don't really think it's appropriate for a host to push a guest to do that (there's certainly no obligation on the guest's part, I had fully paid for those nights already and I was too busy moving to sort out how to cancel the booking - or to research if that would hurt my Airbnb rating in some way).
All that said, when I encountered the hosts in person, they seemed very polite and helpful, which is why I did not give them a lower rating. However, I would not rent this Airbnb again unless they indicated they had made some changes to how they run it. You're better off booking a hotel for the same price and avoid the security issues and the hassling.