Be prepared for stairs, as previous reviews state. Only affected me upon first arrival and last departure (with my luggage), and those times when I forgot something and had to go back up to my room. Plan well and it isn't really an issue.
Stayed there as a solo budget traveler in June 2010 (late review!), and found the rate, location and amenities, including air conditioning and mini fridge, very convenient. Very close to San Marco Square, Rialto Bridge and La Scala. My single room was very clean, had sufficient space and storage. Breakfast was delivered each morning.
No problems communicating with the owner prior to my stay or with staff during my stay, even despite arriving later than I planned and not being able to call.
I definitely recommend this place!