On the outside, this basilica is breathtaking. The architecture and artwork are just marvelous. Now try to get inside- it is easier said than done.
The regular queue that is the free admission is usually no shorter than 45 minutes. We learned of this and went on the internet to pay 3 Euros for a timed entry into a different door, which meant we got a specific time to go back and upon arriving at that time we didn't have to wait at all. Definitely worth it. However, they have a lot of rules that are not enforced very evenly- either enforce them strictly for everyone, or don't have rules! It was very frustrating seeing women with huge, suitcase size purses waltz right in, while my boyfriend's sleek little backpack wasn't allowed. They have a free spot to check your bags, but it is down an alley and out of the way, we almost got lost looking for it. My advice would be to find this place first and check your bags no matter the size just in case before joining any queues to enter. Also, there seems to be a difference of opinion about what constitutes shorts/pants/knees/legs/etc. Just be as covered as possible to play it safe.
Once inside there are signs everywhere that say no photos allowed, but it seems everyone except me ignores this rule. It is really lovely inside, but so crowded you feel a bit like cattle being herded. And all of the interesting things- the altar, the museum upstairs... come at a cost. We thought that going upstairs to see the views and the museum exhibits was worth the extra cost. There are lots of interesting things back there and getting to see the open view of the inside of the church is great.
This is definitely a must see for a trip to Venice, however you really have to be prepared. It is frustrating to have to follow all these rules that may or may not matter, and super crowds are never fun. But I don't know if I'll ever be back to Venice in my lifetime, so I'm really glad I saw it. I could only give it an average rating because of all the craziness with the rules, but I promise you, it really is stunning.