What can I say... There is absolutely nothing to complain about. We had a great time in Venice and a very pleasent stay at the Casa Martini! The rooms are very clean. Especially now in times of corona, it felt like every corner got checked and cleaned twice. Also it was never too cold and the windows are very good isolated, not only in terms of temperature, but also when it comes to noice. We havent noticed any of the multiple bars in front of the hotel. Also if you visit Venice in summer when its really crowded, you can take the "Fondamenta dei Ormesini", which is quite near to the hotel, to get from north to south more quickly. So the location could not be better.
Last but not least, the breakfast ist definetely worth it and the staff is very friendly and uncomplicated.
I can only recommend the Carsa Martini!