The problem with the public "option" is that it isn't really an option at all. On the face of it, it is cheaper (due to subsidy, which comes out of your taxes, making it a wash for middle-class Americans), though with all government run programs, the quality of service (in this case, quality of care) will degrade over time as the willingness of Congress to subsidize at a high enough level to maintain affordable costs to consumers at a given quality of care. Rather than sacrifice by increasing costs to consumers, they cut the quality of care. In addition, if the cost to consumers is sufficiently below market rate, people will flock to the public option, putting private sector health care out of business. Then, when quality of care degrades, consumers are stuck with the public "option."
The government should never compete with the private sector. It should either socialize the health care system all the way or not at all. Government competing with the private sector has never ended well for anyone (see the Tennessee Valley Authority as a prime example), except the politicians and bureaucrats.
I'm all for reforming our health care system: I think health insurance is a scam, and government mandated health insurance (such as we have here in Massachusetts) is an even worse scam. In general, I think most politicians wouldn't know which hole to shit out of if they didn't have someone holding their hands through the process. Naturally, I find it highly unlikely that they are capable of reforming the health care system in any positive way, thus I must oppose their efforts at any reform, and especially at any attempt to socialize the system.