The space is authentic and the location is wonderful. It is a little tricky to find, but once you walk it once, it's easy to get to. Be prepared to climb stairs as others have noted, but it's not awful. The space is very clean. We didn't know that you couldn't use the AC in Venice in October (the host said it's a Venice law due to emissions). The windows get a good air flow going and the view of the canal is pretty. Be sure you close the windows before the mosquitoes get thick or you won't sleep.
Again, the location is awesome. So close to amazing food, shopping, sight seeing, gondola rides, stores, etc.