The AP discounts are almost always better but they were a little more difficult to get this year (fewer rooms made available). For the summer months, Disney offered a flat discount rate to AP holders. For 4/17 - 7/4, the discounts were $25 off Value resorts, $40 off Moderate resorts and $100 off Deluxe and Home-Away-From-Home resorts. For 7/5-8/27 the rates were $25 off Value resorts, $50 off Moderate resorts and $75 off Deluxe and Home-Away-From-Home resorts.
AAA offers a straight percentage savings which varies depending on the season. For Value Season it's 15% off at Deluxe and Home-Away-From-Home resorts, 20% off at Values, Moderates and Ft. Wilderness. For Regular Season it's 10% off at the Deluxes and Home-Away-From-Home resorts, 15% off at the Values, Moderates and Ft. Wilderness. For Peak Season it's 10% off Deluxe and Home-Away-From-Home resorts, 15% off at Values and Moderates and Fort Wilderness. There are no AAA discounts during Holiday Season.
Whether it is worth purchasing an AP depends on how long you're staying and whether you're able to secure a discounted room. Last summer, I got a room at a deluxe resort for 5 nights during value season. The AP discount was $85 off the rack rate. With taxes, I saved $474, more than the cost of my AP. An adult AP now costs $420.68 with a renewal cost of $378.08. For me, it was worth it.
This spring, we wanted to stay at CSR. I could have gotten an AP disocunt at POFQ, but we really wanted CSR. Of course, there were no AP rates for our dates at CSR. I had to settle for the AAA discount. But, I still had my AP from last summer, so it felt like I was getting into the parks for free.
In general, I would not advise purchasing an AP just to get a room discount. With the new MYW passes, you would have to visit the parks about 13 times just to breakeven on admission cost. But if you plan to visit the parks more than 13 times in the course of 365 days, or if you're able to get an AP discounted room for a stay lasting several days, then it may be worth the purchase.