OK, reading the details. First of all, 23% is way too high. Second of all, the prebate is bullshit. We would effectively be subsidizing anyone who doesn't spend money. That is a deal-breaker for me.
With a flat income tax, a person making $10k per year is vested because that person would owe tax on that income. Under the sales tax proposal, a person spending $10k would be getting free money from the government. A great big 'hell no' to that.