After we traveled to Haleakala crater for many hours on hair pin turns, we hit up the Maui Winery. I read on trip advisor that it was a good idea to visit the Maui Winery after visiting the Haleakala crater. It's really about 20 more miles of narrow roads. And after you get to the winery you are probably about an hour's drive to get back to civilization (the airport).
BUT, if you take a step back and say, "I'm on vacation, I'm in no hurry." Then it's totally worth going to. The surroundings are beautiful and serene.
There are winery tours at 10:30 and 1:30. We arrived right on time for the tour, but we weren't very interested. So, we headed right in for free wine tasting.
VERDICT: If you are in the neighborhood definitely stop by. If you are making a special trip, don't bother and just buy it online.