I like the general idea, but it won't achive at least one of it's stated goals, getting rid of the IRS. Somebody will have to collect the sales tax, somebody will have to issue the refund checks, somebody will have to rule on corner cases, and somebody will have to deal with tax fraud. They might call it something else, but it will serve the same function.
The idea of a national sales tax is such a radically different basis for collecting government money that it becomes hard to judge the economic effects.
One of my big concerns is if they are talking about a sales tax or a value added tax? A sales tax applies to every sale, and is thus much simpler but also encourages large conglomerate companies that can minimize the amount of purchasing they do. On the other hand a VAT is more complex and more open to fraud, but more fair for small companies and individual reselling.
In the end I don't think what is critical is how the tax is collected so much as making the tax simple. The entire tax code should fit into a 30 page manual and everything you need to know as an individual paying your own taxes should fit on a postcard.
Jay