I've been to only a few wineries elsewhere, so I'm not super-experienced at what the rest of world expects, but I'll say that this one's my favorite.
Their wines are different - a lot of fruit wines and South Dakota specialties, but they have more traditional ones as well, and a fairly large selection. I think they're surprisingly good, here in little old South Dakota. They usually run $15-30 per bottle. I am a Legacy Cru member, which is a free club with a commitment to purchase a selection of about 4 bottles of different wines, sometimes special ones just for the club, four times a year. They charge me for them, then I come pick them up (or you can have them shipped). There are also members' events throughout the year, and I get 20% off all my wine purchases, which I think is worth it. Whenever I go, I get a free tasting (5 samples), especially because there are always new ones coming out.
The winery also has a lovely restaurant. It is a counter--you seat yourself and they bring it to you. It is a little pricey but I have never been disappointed with their food. Very flavorful and unique, earthy foods. I like to go with a group and get their seasonal open-faced sandwiches, or crackers, dips, and cheeses with a bottle of wine. Sit outside if the weather's good - a beautiful view of the Hills, and their patios are landscaped beautifully. Service is hit or miss but has usually been good.
There is wine-themed merchandise for sale, as well as decor, jams and jellies, and fancy meats and cheese.
Check the calendar for events with music, art, etc. It's small, so it may get crowded at certain times.
They have a new brewery next door (The Miner), so you can continue with a flight of beers (for a price) there as well.