My friends and I booked this half-day tour at the last minute when our original plan for the day fell through, and it turned out to be one of the best experiences of our trip.
The guide - Julie - is awesome. She has amazing knowledge of the local area, and knows all kinds of unusual spots and interesting people - she'll create a tour that caters to exactly what you're interested in seeing. Though we were certainly keen to visit a winery or two, we were more interested in exploring the area in general, and Julie certainly gave us that! We visited a couple of the larger wineries (Rockburn was a great place to stop for lunch, and their wine is fantastic) and a small private vineyard, as well as making a trip out to the lovely town of Cromwell, and visiting all manner of interesting places along the way, and meeting some wonderful people. We really couldn't have asked for a better day - we recommend Funny French Cars to anyone interested in exploring the Wanaka region.
Oh, and make sure you order the cheese platter that comes as an option with the tour - it's all delicious local produce, and goes wonderfully with the wine!