A friend and I stayed at Ugo's lovely apartment for four days, and we would both happily return. It's every bit as attractive as the photos suggest. The location is wonderful - I love Dorsoduro, and this combines being close to everything while still being in a (fairly) secluded back street.
Our only real concern was that one of the two bedrooms is not terribly comfortable for an adult. We flipped a coin and my friend got the master bedroom, which she said was great - comfortable and very quiet. My twin bedded room might be fine for children but I found the bed small and too hard, and noise from the Calle Bianca Cappello disturbed my sleep.
However, I'd still book the flat again, because in all other respects it at least met if not exceeded our expectations. Ugo was helpful and accessible when we had questions. I would recommend this apartment - as long as you take earplugs!