4 stars.
We stayed with Carmen at the last minute. Our prior AirBNB arrangement was unsuitable, so we found availability with Carmen. The apartment itself is good -- three large bedrooms with plenty of beds for everyone. The beds were decent quality too, not super hard or squeaky. Internet was fast and stable. The washing machine worked well and there were plenty of clothes pins to hang up the clothes on the line. The building was very quiet -- no loud neighbors and the street noise was minimal. Most tourist sites are within a 20-25 minute walk across the bridge. There are several grocery stores very close by.
We had a few issues -- (1) The dishes, glasses, and silverware in the apartment were not clean. My assumption is the dishwasher was loaded and never run, and then the dishes were put away. I assume this is a one-off situation, but I did spend about 30 minutes upon arrival hand washing everything so I knew it was clean. (2) Several of the door jam sections have a tendency to fall off. They aren't hard to put back, just pop them back in place, but it was annoying and one time my son had one fall on his head. One of the bathroom doors is very hard to open and gets stuck half way in. None were deal killers, and I suspect the kitchen issue was unusual.
For the value we were very pleased with the apartment. 4 stars!