Where to begin? I think you need to be suspicious when the most critical questions in their FAQ are glossed over with spurious logic and weak rationale.
For example, they justify including medicine and food in their tax scheme because to do otherwise would unfairly benefit the wealthy, who they argue, spend more on medicine and unprepared food (Never mind that, in most states, medicines are tax exempt and senior citizens on fixed incomes still struggle to afford the drugs they need; somehow the 23% price hike is justifiable as long as it doesn't benefit the wealthy).
My problems with their scheme in no particular order:
1. The national sales tax unfairly punishes the working poor, retirees, and anyone on a fixed income (students included).
2. Small concern, but it unfairly punishes small businesses that work in the post-retail sector, and those who rely largely on the retail sector for supplies.
3. It creates a market place that is far less attractive for foreign investment and import, which makes absolutely no sense in a largely service based economy.
4. It opens an enormous loop-hole for anyone who can pass personal expenses off as business to business transactions. Bill Gates will probably continue to use Microsoft's toilet paper, and stay in their executive suite, and drive their executive car. Same deal for anyone who can purchase bulk goods abroad.
5. It'll drive business to e-bay. Who really wants to help e-bay?
That's all I got for now. I'll read up some more later on.