I have not eaten at Osteria Enoteco, so I cannot compare it with Al Covo. I can say that I have eaten at Al Covo on both my visits to Venice, first in 2018 and then in 2023 and I would happily visit again on my next trip. This is truly a family run restaurant, the owners, Cesare and Diane, are joined by their son (who works alongside his dad in the kitchen) to create hyper local Venetian cuisine.
What I loved about the restaurant is that it is an intimate dining experience (we ate inside) with attentive service. The owners, Cesare and Diane are actively engaged with customers. We had the opportunity to spend some time with Diane and hear about how a Texan fell in love with a Venetian and came to Venice to build their restaurant.
The Al Covo menu changes based on what is fresh and in season, so the menus on the website are likely to be different than when you visit the restaurant. I love fish and Al Covo sources fish from the Adriatic and often serves it as a crudo, baked/grilled, or with pasta. Their presentation is inventive. For this post, I went back to my photos and the standout was a pasta with crab served in a crab shell. Their desserts are made by Diane and you'll see some of her Texas roots in certain desserts, for example in the Cheesecake we had, the crust had pecans.
The other feedback about the service is that Al Covo is very accommodating. My friend ordered a pasta with sardines despite the fact she does not like sardines (don't ask, we tried to dissuade her), the server noticed she wasn't eating it and asked if she would like something else. She did not want anything of the other pastas on the menu and asked if they could make her pasta with a simple red sauce. The server said of course and delivered a delicious pasta dish exactly to her liking.