Our tour was so-so. Our guide took us to only 3 wineries, which is a serious knock, since this tour usually visits 4. We could tell that our guide was trying to kill time to make up for the missing winery, and didn't give much of an explanation as to why we were only visiting 3. In addition, our guide made very little effort to talk about the region or about wine production; she really was just a driver for us. That is a relatively minor gripe, but was compounded by the fact that we only visited 3 wineries, for which it almost feels like we should have been offered a partial discount.
Further, 2 of the 3 wineries we visited simply didn't have very good wine. This is a matter of taste, of course, but our entire group agreed that the third winery was far and away the best. It felt a little odd that were taken to 2 mediocre wineries; as I see it, part of the guide's job is to know the local wineries and select those that offer high quality wines.