I have not been, but making plans to see if I can attend in 2013. The last 5 years I have had a major and mandatory work meeting the same week.
Everyone I know who has been says if nothing else the taxidermy and art work is worth the price of admission.
You must be an SCI member to attend. You can join ahead of time or you can purchase new membership at the door if I understand correctly.
In addition the auctions can be a source for some great hunts, tags and gear at reduced prices.