My friends and I truly loved the Sancerre wine tour with Brice! This was an amazing tour and worth the money! You get out of Paris and see some beautiful bits of French countryside. And the wine is great, of course! It's an absolutely wonderful day! It was everything I hoped it would be and more.

The longer version if you want more details:
I had a little bit of trouble initially booking the tour just due to my credit card blocking the charge and then not correctly unblocking. I used the contact info on the tour website to get help and Brice responded very quickly and helped me get everything booked and straightened out. He also made sure I received some tour day info via email, which originally had been undeliverable. So I'd say the communication and responsiveness was really great even before the tour itself.
The tour is a long day - but worth it! Definitely follow the recommendations to dress in layers. Depending on the time of year (we went mid-October) it will be dark when you leave and dark when you get back to Paris. Recommend bringing whatever you need to be comfortable being gone all day (e.g., earbuds or book for some of the driving time, water, power brick to charge your phone, etc.).
The tour guide, Brice, does everything. He's your tour guide, driver, and translator (when needed) and he is perfection! He clearly loves what he's doing and is knowledgeable about the area and the wines. It is obvious he's put a good bit of work into finding just the right places to include in the tour. There were a couple of great photo stops. The goat cheese farm was really interesting and there were baby goats to pet (who doesn’t love baby goats?!). Lunch was delicious! There is some free time to wander through a wine museum and then back through the cute little town itself. Both of the family wineries were excellent choices because they highlighted different types of operations. I learned a lot and really, really enjoyed meeting the winemakers and drinking their delicious wine!