Basically my concern is that in the Senate, once there's actually a bill to be voted on, there will be enough details in the bill which sound bad - some of which probably are bad - such that Republican can legitimately make the case that the bill is not something people want. They'll start throwing around numbers - maybe true, and maybe false, but hey, views differ - like "the government will force you to spend 20% of your income on health care." They'll make it sound like a tax, they'll hype the fines, they'll point out that the bad ungenerous bill they encouraged Dems to put forward is, in fact, a bad ungenerous bill.
So far criticism of the bill has involved death panels, undocumented workers, and abortion. Just wait until the (somewhat) real criticisms start!