I knew a GAL once...oh wait, different story
I go to both the GAL conference as well as ASIA and enjoy the differences. The West coast has some legendary classical builders so at GAL there is usually a more even mix of steel string to classical...some years you will find at either more archtop builders also.
A good number of pro builders go to both but it is nice to have two different orgs, 1 more east coast oriented and the other more west coast in case you live on one coast or the other. Each Org's get togethers are scheduled in alternating years from each other so for the severely addicted (me...) you can go to both.
Both have very fun auctions and the vendors always get all of my money...
At the ASIA symposium Bobc and Steve Roberson had out such amazing woods that you would have thought there was a competition to see who's wood would make you drool faster...it was a tie.