Probably the most damning aspect is what getting that level of performance from your home PC would cost:
"Of course, in terms of overall value for money, OnLive says you don't require any specific gaming hardware and you'll never need to upgrade, so this in itself sounds like you're making a massive saving, but the fact is that the PC required to run the system isn't insignificant. Unless you're running on a laptop, upgrading it with a relatively inexpensive graphics card will offer an overall gameplay experience that effortlessly beats OnLive on quality and response. Perhaps by the time expensive next-generation hardware is unleashed upon us OnLive's value proposition will increase accordingly, but until then the value just isn't there."
Link to Original Source