OK, Here is why I personally have never attended.
Lets price this out.
Full Registration: $700
Boot Camp (several options) : $200
Spouse Meal Option: $125
Virginia Winery Tour Option: : $150
Total: $1175
Throw in at least 2 nights lodging at the Conference Hotel so you can be close to all the "action" : $500 (with taxes)
Thats a pretty expensive weekend.
I attend my local State "Vine and Wine Conference" for Winery and Vineyard owners each year. It is open to Amateur winemakers as well.
2 day Conference with full continental breakfast each day, full hot lunch with multiple meal options including Vegan, afternoon snack break each day, optional evening dinner, full access to exhibitors, wine tasting, multiple tracks (professional and amateur) : $200
Each year we have several speakers who have also spoken at the Annual Winemaker Magazine Conference as well such as Shea Comfort aka "The Yeast Whisperer". Its close enough for me to commute each day so no need for a hotel room.
Since you can find most of the information from many of the speakers in the Winemaker Magazine or elsewhere online unless you just really, really want to press the flesh with a speaker and fellow winemakers you can easily find the answers to all of this online, in forums, or in the magazine for much much less than what you would end up spending at the conference.
I find it very overpriced.
I asked the same question, it's hard to believe that no one from this forum is attending