We came to Marzamemi for my brother's wedding which meant that a lot of other guests were at other rentals and hotels. Our experience with Rosa was superior to everyone else's experience! Rosa was great, giving us some tips at check-in. And her apartment was fantastic compared to others' places-- the location is quiet and just a 10 minute straight walk to the town center, the shower was wonderful after a day at the beach, she had a beach umbrella for us to use, the balcony was nice for a morning coffee, and (most importantly to us spoiled Americans) the air conditioning in the bedroom was freezing cold!
I can't recommend Rosa's place enough if you're coming to Marzamemi. There's no better value and it made our trip an absolute delight!