But despite his claim, the only difference cited by Sununu wasn't actually part of the Medicare plan. He said that unlike Ryan's budget plan, Romney would repeal Medicare savings signed into law by President Obama. But those savings are actually a good thing; they lower the cost of Medicare without touching benefits. And the only reason they aren't in the Romney budget plan is that Romney's budget plan has almost no details.
So, despite Sununu's claim, there is really basically no difference between what Ryan and Romney are proposing for the future of Medicare. The fact that Sununu would nonetheless claim that the plans are "very different" tells you everything you need to know about how afraid Republicans are of defending the Romney-Ryan plan on its merits.