Great location! I stayed at Karen's place with my partner, our toddler, and my teenage nibling. The reviews were accurate. Here is what I would add:
Location: Excellent for all kinds of tourists. We were minutes from everything we wanted to see/do. It is very close to Waverly Station, but be prepared for a short but uphill journey from the station. I think this is probably true for most old town accommodations.
Stairs: This was my biggest concern when booking, and we were pleasantly surprised. The stairs were not so bad! I was nervous because we had to carry a stroller up and down every time we went out. We are all healthy, but not especially fit, and it wasn't a problem. I didn't even get winded. The stairs were a little dark at night, but as we were there in the summer and didn't stay out too late, the light from windows was sufficient.
Noise: Not too bad, but not completely avoided by a Monday to Wednesday stay. My toddler and nibling slept through it. I expect this is the tradeoff for the super convenient location. I'm a light sleeper. So, it sometimes woke me up, but it didn't bother me much.
Old-building quirks: As noted in other reviews, the building is old which makes it special in a few ways. The toilet is slow to fill. This could be embarrassing if you are on a romantic getaway, but it didn't bother us. The water pressure in the shower was great-better than what I have at home.
Value: This place was big! It was far more space than we needed, and the views were incredible! I'm glad we opted for Karen's place over paying for two hotel rooms or staying at a smaller flat. I would stay again!