As I see it, Intel has one advantage going for them. The x86 architecture is superior to the ARM in terms of raw performance. The other half of this advantage is Intel's recent ability to make it very efficient. That said, we'll see how it stacks up to ARM when they strip it down enough to sip power at the same rate as ARM. ARM was designed with the idea of low power consumption in mind, so one may consider that its home field. However, a home field advantage only goes so far, and we'll see if Intel can muster enough R&D to tweak its architecture to play on it realistically. If they do pull it off, 2 things could happen.
1, they can't deliver at a price point to displace ARM in the smartphone / tablet market.
This is some what likely in my opinion, given that Intel is one company VS several, as ARM licenses its technology out to others while Intel is the sole developer and manufacturer of said technology.
2. They deliver at a competitive price point, and deliver matched or improved performance. This could be potentially disruptive to the current "ecosystem" of mobile devices, since joining mobile devices with current desktop PC architectures simplifies development to some degree, and would potentially change the battle as far as desktop / mobile unification. Especially seeing as how Windows 8 is being designed as a universal OS, but basically being an entirely separate fork from its x86 twin. That starts the similar issue apple faced when transitioning from the powerpc arch to x86. For years they had to build 2 versions of everything, as did developers. Not an elegant solution.
However it remains to be seen, since things do tend to gain a momentum of their own at some point, and we either very VERY close to being beyond the point of any return for an architecture switch in the mobile market, or already past it
My .02