Most of the arguments aren't really that impressive though, and suggest Intel is feeling threatened by the NVIDIA Ion. Here's a snip from Bit Tech's article:
The first point that Intel makes about Ion is that the chipset is nothing new, saying that it’s "rather a SKU of the existing MCP79M/MCP7A chipset family (branded in part as GeForce 9400M, GeForce 9400, GeForce 9300, GeForce 9100M G or GeForce 8200M G." Intel points out that "despite Nvidia’s continued execution and power problems with this chipset, Nvidia is partnering the same chipset with an Intel Atom processor and creating hype around what it calls the 'Ion Platform'."
A major problem here, according to Intel, is that Nvidia is "attempting to re-use an integrated graphics chipset designed for the notebook and desktop system price points into the netbook and nettop system price points. This in turn leads to higher costs as well as high power consumption," says the company.