You've basically got it. It is a chance to hear new gear and meet your fellow Headfi enthusiasts in real life. Often times industry folks will be there with demo gear as well. Don't be shy if you are new to this hobby, either. There is no judging of rigs outside of maybe marveling at some of the higher end stuff that shows up.
Ok, awesome. Thank you! Is it necessary to bring your set-up, or would I be able to just come and enjoy everyone else's? What would I need to bring in order to attend/make the experience as great as possible? Is there a cost of entry or anything like that?