I'm not a fan of Romney's, as those who know me personally will attest. I do think he's the lesser of two evils, though, so I'm about to defend him. I've noticed one of the new Democratic talking points after the Obamacare decision is that Romney is a poor person to carry the message against Obamacare since he created Romneycare in Massachusetts. I feel just the opposite--I think he's one of the best people to do so. Who better to point out the flaws in Obamacare than the person who has experienced them firsthand? For example, if you're a football player heading into the Super Bowl, who would you expect to get he best advice from--a player who's never been, or one who has, even if that trip wasn't a successful one?
If I were writing up the GOP talking points, that's how I would try to shape that message, anyway. Point out the differences in the two, and point out that your candidate is not only qualified, but uniquely qualified to elaborate on Obamacare's pitfalls.