For me, the scariest thing about this plan is that it would allow you to buy health insurance from any state. That's one of those things that sounds like a wonderful new freedom, but insurance is regulated at the state level. Being able to buy from any state means that all the insurance companies could relocate to the state with the least regulation, and pull out of anywhere else.
Do you know why all the credit card companies are located in just a couple of places? Because those places have the least regulation. Within a few years, all the insurance companies would have moved to Idaho (or wherever), and we'd all be enjoying the improved customer service and coverage that would come about as the result of this race to the bottom.
Oh, and, as Krugman points out, individual coverage has three times the bureaucracy associated with it as employer-provided insurance. So look forward to more corporate bureaucrats standing between you and your doctor, making rules about what kind of care he's allowed to give you.
If you think I'm kidding, let's talk about how many times my insurance company, which is contractually obligated to provide me with prescription drug coverage, has argued with me about the drugs my doctor has prescribed. One of those was to prevent me from going into anaphylactic shock and dying while they tried to figure out what food I was allergic to. Good times.