This is an informal non-AK sanctioned event that has grown into quite a gathering. Often we'll have upwards of 50 people there with some cycling in and out.
I would say that this gathering is as much about being with like-minded people who enjoy the audio hobby as it is about the gear. That being said, if you're a subscriber, look for the Frankenfest buy/sell thread for what folks are offering. If you express interest in buying an item, you will be able to get it. Often things are sold ahead of time and just swap owners at the fest.
Routinely, someone will only lug stuff there if someone expresses interest in the buy/sell thread, but the last few Frankenfests have had more, and better, gear than I've ever seen before. There's also been quite a bit of good music for sale.
Not only that, there are reasonable hotels nearby.