In the past few years Asus has been more and more surprising, and they seem to have a hunger for innovation, and trying new things that the other companies don't seem too willing to try. They made the netbook popular, then they were among the first to make the Transformer tablets popular, then they had the Padfone that integrates into a tablet, and now they're going to be first company that puts both Android and Windows 8 on the same device.
That's risky by itself, because I doubt Microsoft likes that very much, especially with the new UEFI boot, which allows them to be some kind of gatekeeper for other operating systems on machines that will come with Windows 8. But Asus is giving that a try anyway, whether Microsoft likes it or not, with their upcoming Transformer AiO machine.
The Transformer AiO is not based on ARM, but on x86, so it has the x86 version of Windows 8, and Android 4.0, which can work on both x86 and ARM, and most apps should work (although the native ARM ones will be emulated on x86, unless the developers compiled them for x86, too). The way it works is that when the machine is docked, you get Windows 8, and when you take it out, it immediately switches to Android 4.0.
Clearly Asus thinks that Android 4.0 is better suited for the tablet form factor than Windows 8 in this case, because on tablets Windows 8 has no optimized apps yer, aside from a few from Microsoft, and all the "legacy programs" are all optimized for x86, are generally slow compared to mobile apps, and are not optimized for touch either.
My only complaint, is that if they were going to do this, I think Windows 7 would've been a lot better for the "desktop mode" than Windows 8, which forces you into the tablet interface whether you like it or not. I think it would've made more sense to keep Android for the tablet mode, and show Windows 7 once you dock it, and then use it like you'd normally use a computer.
I also don't expect this tablet or hybrid device to have that much battery life compared to ARM tablets and the Transformer Prime. Plus, nobody says how much these things will cost this fall, and my guess is that they will cost a lot. Expect them to be significantly more expensive not just compared to current high-end tablets, but also compared to ultrabooks.