I love staying in Dorsoduro when I visit Venice, and Ca’ Grifalconi was a wonderful base for our stay. Campo Santa Margherita is mostly non-touristy, lively, with a few nice bars and restaurants and a handy little supermarket. It’s well situated for Vaporetto stops and just a short walk from Piazzale Roma (in case you arrive from there).
The apartment is on the third floor overlooking the Campo, fortunately with a working lift! It was spacious with two double bedrooms and a good sized living/dining space and modern bathroom. It had good wi-fi and everything else we needed for a comfortable stay.
Maddalena’s mother met us on arrival and showed us around. Her English was good and she made us feel very welcome. Both she and Maddalena were contactable in case of questions arising.
My only issues were these: because the Campo is quite lively, it was rather noisy at night, and we kept the windows open because it was hot. (Others have said that, with the windows shut it’s not bad, but we didn’t know how to operate the AC.)
Plus I found the mattress in the red bedroom very hard — but that is very much a matter of personal taste. My friend said the other mattress was ok.
I would certainly recommend Maddalena’s apartment to visitors to Venice.