Welcome to the forum.
The trolls tend to be very well behaved for the most part.
I have been a member for almost 4 years now and I've probably used my discount two or three times max. It was great when I found myself somewhere I could use it but locally most of the places I go give me as good or better discounts based on my homebrew club affiliation so I don't use the AHA discounts.
I do love getting the magazine every other month (wish it was more often but you take what you can get). The opportunity to attend NHC (The conference) and compete in NHC (the contest), the ability to vote for the governing committee, and the satisfaction of knowing you are helping out a good organization that helps expand our hobby and protect our rights are the big selling points for me.
You do get a card to show for discounts.