We can only echo the numerous positive reviews which were also the reason for us to book this place and indeed our expectations were more than met - but we'll add our own perspective here:
Appartamento con terrazza sui tetti is a cute little flat located in a nice street of Ortigia close to the sea (you can hear the sea roaring and even see the sea a tiny bit between the buildings from the terrace) and also a little apart from the buzz of the touristy center of Ortigia. The island is very small so this flat is perfectly close to everything and to the new town/ bus station etc. There is a great food market just around the corner where we went frequently to buy fresh vegetables, fruits, cheese and bread.
As previous guests mentioned, the flat is very nicely decorated, contains all items you need to feel at home, arranged in a thoughtful and tasteful manner. In the kitchen, we found not only olive oil, coffee and spices but also some basics that Maria Laura had bought for us to give us a soft landing. That was such a welcoming gesture. The flat is not huge but it is very cosy and has a great roof terrace that we enjoyed a lot. It is also really calm- no noise whatsoever- and therefore very relaxing.
We also liked Maria Laura a lot: she is very tactful and not intruding at all but very friendly and always ready to help. It feels like she really really cares for her guests and would like them to have a nice experience in Siracusa. Her English is perfect- we were even not sure in the beginning if she is really Italian ;-) but she is. At first I was a little sceptical if it would be somehow strange that we'd need to cross the hallway of their apartment to enter ours in the backyard but that was no problem at all.
We had a wonderful time in the apartment and in Siracusa. Even though the weather was not perfect. Siracusa is a really charming city and it is recommendable to stay a bit longer to explore all its angles beyond the tourist sights. You can also do a lot of trips in the area like Noto, Modica, Vendicari.