My bf and I did the "night markets" tour of Shanghai. We cannot speak to the other tours. But... generally, here's how we felt:
This experience felt more touristy than authentic - the "strip" where the food vendors were situated felt more like Vegas that authentic Shanghai.
Went to 3 different restaurants on tour. Each restaurant seemed to treat our small group (fewer than 8) as a nuisance than a welcomed guest. We were put upstairs in a storage area at first one. Second one, they dragged a table outside the restaurant. Third, was the friendliest. We actually were integrated with the locals!
We ate many things including grilled veggies, crayfish, snake (tourist trappy), bao/Chinese steamed buns, ma po tofu, a few pork dishes, lamb kebobs, and two types of noodle dishes.
Tour guide's food knowledge and sharing of Shanghaiese culture was just average. Would have loved to have learned about the cooking techniques, the ingredients in the sauces, the history behind the dishes, etc.
The noodle vendor on the street had probably the best dishes (rice noodles and wheat noodles both great) as were the traditional Chinese dumpling and pot stickers with the vinegar dipping sauce that our guide purchased for sharing at the first restaurant. We would have rather walked around the streets of Shanghai to experience that culinary side instead of the restaurants which weren't welcoming nor a great taste experience.
This was definitely NOT the highlight of our trip especially at about $75/per person.
Better to have a personal guide walk around with you for a few hours at a lower price who can translate for you as you experience all the dishes and flavors.
I hope to hear UnTour Shanghai makes some improvements to their Shanghai food tour experience in due time. It's overrated.