I think that it depends on the agreement that your organization has with TaW. My brother works for Siemans and he gets fabulous prices on Disney tickets. But then, Siemens is a Disney corporate sponsor. He's always had good luck with his purchases from them.
I have access to TaW through my health insurance. I can purchase a 5-day hopper (e-ticket delivery) for about $10 less than the price on UT (actual ticket delivered to my house). One thing that I did notice is that TaW adds their "taxes and fees" at checkout, while UT includes them in their ticket prices.
As for AAA, they have the highest prices for me. But every region sets their own discounts, so YMMV.