Sandra's place was at an excellent location, just in front of Copacabana Beach. We felt the neighborhood was very safe with everything we needed near the apartment (supermarkets, the subway station Cantagalo, restaurants and, of course, the Beach). The place was comfortable, clean and well-equipped.
We did not meet Sandra personally, but she was very diligent with our questions during the check-in process. One minor caveat though, the neighboring apartment is being remodeled and there were some noises during weekdays (at least at the time of this review). Since we usually went out, this wasn't really such a great inconvenience.