I've used AAA to get a small amount of "seed money" foreign currency but I agree, their exchange rates can be awful. A couple of years ago before traveling to the UK, I stopped into a local AAA store to ask about buying one of their "TipPaks" or whatever they call them. It's $100 worth of foreign currency, or maybe it was £100, I forget which. Anyway, the guy at the counter was helpful, honest, and discouraging.
He said that the paks of GBP they had on hand, had been purchased at an exchange rate that was higher than the current rate, so the paks wouldn't be a good thing at all since they were priced to cover the exchange rate at which they'd been purchased. That was an interesting insight into how AAA (at least here in Colorado) operates, and why their currency paks can be such a bad deal especially when exchange rates are volatile.
I thanked him and left without buying any £££. At my departure airport before I joined the security line, I got about £150 at the currency exchange counter. It wasn't a flaming bargain, but IMO it wasn't a ripoff either. It was worth it to me to have some cash in hand when I landed. I do use ATMs while traveling; great exchange rate and my credit union doesn't tack on foreign transaction fees.
I use plastic more than cash on foreign trips these days, just as I do at home. Times change and my habits change too. Then I read the news from yesterday that the Visa system crashed in Britain. That kind of thing makes me decide to continue to have some cash on hand when traveling.