Although unsaid, and not proven, the Ryan plan anticipates that the cost of health care will be less under his voucher plan because the patient will have skin in the game and use his vouchers more wisely.
The flaw under the voucher system is each individual will need to buy the best insurance he can with the voucher and then we are back in the same boat. What the health industry charges for its services and how often the services are used are back in the hands of the providers, with the cost covered by the insurance companies.
The cost of insurance will then rise faster than the value of the voucher and health will decline.
The Declaration of Independence says "... that among these are Life, Liberty and the pursuit of Happiness." The question is are wealthier Americans deserving of a healthier, longer life than the less wealthy? If we are a nation believing in basic Judeo/Christian values the answer is no.
Update: August 22, 2011: Here is a good comparison of proposed Medicare plans.