According to my experience and visits, I would say Sula Vineyards in Nasik is the best vineyard to visit. It is one of the largest vineyards as well, it is also a resort that includes a swimming pool, spa, restaurant, and games room, so pretty much everything to enjoy your stay there.
Another factor is whether you are looking for something in particular when visiting a vineyard, such as views, or experience, this also makes a change in the best vineyard in India, but overall I think that Sula vineyards in Nasik is the best if you want to visit.