Last year, we took a Chianti wine tour operated by Walkabout Florence (Chianti Wine and Food Safari?). We actually booked through Viator...
This tour far exceeded our expectations. We're not really "escorted tour" people but this one was a clear exception. It was a small group tour and both the tour guide and the driver were wonderful.
We hit three wineries, including the lunch stop, and the town of Greve in Chianti. The wineries were wonderful and we tasted three wines at each stop. The tastings were also accompanied by local food specialties and hosted by wine experts. BTW - I've looked up some of the wines we tasted and all are considered premium. Principe Corsini and Ciniano were the two wineries, in addition to the agriturismo below, that we visited.
To be honest, I wasn't expecting much out of the lunch as I had read reviews of other tours that really criticized the lunch services. Some reviewers (of other escorted wine tours) even posted pictures on what appeared to be grocery store prepared food being served on disposable plates... Well, this tour's lunch couldn't have been more different. We stopped at La Cantinetta di Rignana and had a wonderful five course meal with four courses of wine - all served family style. The courses were almost cicchetti in nature with a variety of selections making up each course so everyone could sample each item. The agriturismo staff did a splendid job of explaining each item being served and how the wine paired with it.
This tour was the highlight of our Italy trip for sure. As you can see, I would not hesitate to recommend this tour.