This is a GREAT place! It really is right by St Mark's and the Rialto bridge. This is SUPER important because getting lost is really a thing in Venice, and being that close gives you an area to more easily find. In fact, I urge you to print a map before you arrive - their directions are excellent, but having a map will give a bit of an edge as you read them (you'll be amazed at how much easier those directions look after you've been in Venice a few days). And your phone maps are not always correct - don't rely on them.
Francesco & Nina are so nice, and SO good at responding to issues. I mentioned something they might want to look at and she immediately responded and was ready to come over the next day. They were also really great resources for questions I had like the best way to get to the airport upon leaving (seriously, there is a boat that goes directly to Venice from the airport). They know everything and are a great source. I HIGHLY recommend staying here.
Hey - when you go to Murano, check out the Glass museum - it's incredible, and definitely see the Empathic project exhibit too - https://puntaconterie.com/en/empathic/ - I loved it!
One more thing - I'll save you another hassle - bring light luggage. You can't get anywhere in Venice directly - it's all about walking, and that includes bridges with stairs.