Be very careful what you wish for.
IMHO with vouchers will eventually come government control. As soon as private schools have a certain amount of money from the government, regulation will follow as surely as night follows day.
It will start of benignly enough with some kind of "standards", but within 10-15 years private schools will all have to do the condom on the banana trick to keep their voucher money. And, sooner or later the NEA is going to see the light and accepting vouochers will mean the school has to accept the union.
At this point we will be in a terrible pickle--no really private schools will remain and the government will have control of all education.
Learn to pay for it and you will have control forever.
Call me a snob, but I like the fact that the parents at my daughter's school are paying through the nose to send their kids there. We sacrifice alot in order to be able to do it and I like the fact that the other parents are doing the same. It makes me think that they actually care about how that money is spent and how their kids are doing.
Yes, the govt school generally suck, but so do alot of the parents! Schools are not babysitters.
Better to just scrap the whole compulsory attendance/taxation scheme.