Sarah's appartment is on a small sreet just off Campo Santa Margherita. Just the right size for two, it can accomodate up to four, say a family with two kids (4 adults would be a crowd, though). The appartment was as it looks in the pictures. Everything we needed was there and communication with Sarah and Cristina (the lady who checked us in) was fast and unproblematic. The only drawback was a distinct smell of dampness when coming into the appartment, but nothing you can't live with.
The location is perfect if you want to be close to but not in the middle of the tourist frenzy of Venice. This is a mostly residential neighborhood, so you get a feeling of living with the locals. Campo Santa Margherita is a really lively place, busy throughout the day, but especially at night, when it fills with young people hanging out.
All in all, a most enjoyable experiance.