There has been a lot of talk about developers moving to OpenAL after learning that Vista does not support DirectSound 3D hardware mixing. The biggest reason for the functionality going away was that unstable audio drivers were causing almost as many blue-screens as unstable video drivers. Direct hardware access doesn't mean a damn thing if the machine won't work because of either an app or driver bug.
I've got five major issues with OpenAL and Vista.
The first is that it is bypassing the HAL in Vista so we will yet again be at the mercy of the driver developers. With Vista, Microsoft has made system stability a cornerstone of the operating system. I don't like the idea of opening a backdoor to companies that can't even be bothered to fix blue-screen causing crashes in their current drivers.
The second is that while it started as a joint effort between the Loki Entertainment and Creative Labs, it has turned into a vendor-driven API. Remember Glide? Vendor-driven API's can be dangerous, especially when the vendor driving it has their stock price is barely $1.50 over their 52-week low, over $10 below their 5-year high, and facing stiff competition on nearly every front.
Third, audio config testing efforts are going to go through the roof with OpenAL games. I go to Creative's developer forums and read things like, "Well, it works on a Creative card, but on this other card, it crashes," and the response back is, "I'm glad to hear that it works on a Creative card." Piss-poor support is what led to the creation of UAA in the first place.
Fourth, because OpenAL's functionality maps to resources available on the host sound card, there are additional issues with the API design. For example, there is no way to query what the maximum number of allowed buffers is. Instead, you have to try to create the buffers, and if the API doesn't cause an access violation because of a null pointer exception (a common occurance), you then check the return value and if the return code happens to be "that's too high," then you decrement and start over...blech.
Finally, some of the titles listed may use OpenAL, but they also use Miles Sound System as a fallback for cards that don't support OpenAL. Why the hell would I want to use an audio API that doesn't work on several popular sound chipsets? If I have to license another sound library just to fill the config gaps in yours, I may as well use what I'm paying for to the fullest.