Stopped at Sardine for brunch and it was a fairly good experience! It's a french seafood place, so if you're not into that type of food, I wouldn't recommend it. It's right next to Lake Monona and has a beautiful view of the lake if you're sitting on that side of the restaurant. The parking lot is next to the lake, but there's a decent amount of street parking available near the restaurant area.
Beyond the location, the food was good but not AMAZING. I was hoping to be a little more impressed, and to be completely honest, the food itself was perhaps a 3.5 while the ambience/location bumped it to a 4 star review. The service was relatively slow (it's fairly busy - I recommend a reservation for the weekend), but it wasn't unbearable. The restaurant gets very packed and busy, so I would expect a little bit of a wait for both the food and to get a table.
So back to the food - I got the baked sausage + eggs and my friend got a charcuterie plate with a side of fries. The fries were actually the best part of the meal, in my opinion! They were DELICIOUS and much better than the typical fries you get. The sausage and eggs and charcuterie plate were good, but nothing to write home about.
I would like to return for dinner sometime for sure! I totally recommend stopping by if you're looking for something that's not the typical american food that's omnipresent in Madison.