I don't know about these things - I've attended two in Long Beach and have been impressed only with the variety of people trying to sell me stuff.
I admit, that I didn't attend any panels so that may be an attraction for some people.
At this year's Expo the only booth if found of any interest was the Animas Insulin Pump booth where I learned a lot about their technology and their joint venture with Dexcom (which, disappointingly was NOT there). I jokingly asked the rep if it played music and was surprised to find out that "yes" it does! You can download your own ring-tones to the pump! No THERE'S an essential feature.
But I couldn't buy a pump there. I couldn't even complete the paperwork - because I didn't bring my doctor or my insurer with me.
In any case, the Expo basically wasn't really worth the price of parking for me.
How was it for you?