After years of staying in dirty, overpriced hotels in Venice itself, I decided to try something different. I gravitated towards Certosa Hotel for its high ratings and interesting location and I must say that it exceeded all my expectations.
Isola la Certosa is about a 5-minute boat ride from the nearest stop in Venice proper (and about 10-15 minutes from San Marco). Though it may sound like an annoyance, having this little buffer is something that I welcomed. Venice itself is a beautiful place, but overwhelming to say the least. Eventually, you will tire of constant crowds, knickknack stands, and pizzerias blocking you at every turn. Returning in the evening to an island that has nothing but your hotel, its restaurant+cafe, and a nature preserve is a good way to reset yourself for the next day. Boats run very frequently and, when they aren't running due to scheduling or excessive fog, the hotel has a free shuttle service to near the Sant'Elena stop in Venice.