I love audio shows but have never been to Axpona.
Audio shows are often great in two main ways: You get to see and hear all sorts of kooky, wild audio products as well as some that are actually impressive. And it's almost always only a few set ups at best that one is impressed with. The usual result I think for many of us is to have had some fun, but also we come home being all the more happy with our own systems "Mine sure sounds better than that $80,000 set up!"
As for vinyl at the shows, it generally gets a thumbs down from me. Though I like vinyl and I do indeed like to see cool turntables at the shows, I personally don't want it as a source for any of the systems, given it introduces colorations not only from the source itself, but who knows what colorations are coming from the cartridge, poor set up of the turntable etc? My heart usually sinks a little bit when I find a system or speakers I am very curious about at a show, but they are playing vinyl. I'd prefer they keep the turntables on display, off to the side
(Unfortunately many rooms pander to both the current vogue of vinyl but also the idea vinyl is a great or "better" source than digital...yeesh...)