We will have to differ with the rave reviews of this tour. Our only comparison was the bike tour we took in Sonoma county, where our tour guide guided us to lovely wineries, came in with us and pointed out the highlights, provided lunch and snacks, and was at our side all day,
After this, we were surprised that David our guide said "so where do you want to go?", sat in his car while we went to each winery alone, and (when we said we weren't thrilled with the wines we tasted at one place), made a critical comment about how we must not like sophisticated wines. Then he presents us with some Sophia Coppola pink sparkling wine as a gift, which is not sophisticated wine at all.
Add to this a pre-journey stressful snafu, getting an email saying our tour was cancelled because we didn't email him back (when we actually had) and I would recommend looking elsewhere.