AAA doesn't show the full price including tax until you add something to your cart and then go look in it. I wish they listed the prices inclusive of tax the way UT does. Makes it so much easier to compare apples to apples. The OP didn't say how many days they are looking at and whether there are any add-ons. It really depends on the length and type of ticket which ends up being the better deal. I know when I bought in February, UT was the better deal, but I was looking at 3-day with PH. I think at that time 3-day without PH AAA won by just under $2 a ticket.
Yeah the margins on tickets 3 days and less are pretty thin. In fact many of the re sellers charge more for a single day pass than gate price! Disney gets their money upfront, after day 4 its a wash for them, and they rely on accommodations, food, merchandise revenue.