What we loved : the location, very nice area of the city, walking distance to everything (if you dont mind walking), elevator is a big +, cosy little (very little) flat with a nice view of the roofs. Kithen is very small, not equipped for major cooking which was fine with us because we spent most of the time outside anyway. Betty was very kind to let us leave our bags after checkout for a few hours as our train was only in the evening.
Our only complaint is that it was not as clean as we would expect, lots of hair and dust on the rugs and even nails, shower curtain was stinky and both sinks were clogged, Betty tried fixing that with an unblocker but it didn't really make it any better. The flat felt tired and not fresh in general. I guess we payed extra attention to that because we were travelling with a baby. If it was cleaner it would be a much nicer experience.