I am of at least two minds about vouchers :-). As an improvement over the current situation, especially for children in the worst public schools, I support vouchers. Anything that gives parents another option for their children is positive, just for that.
However, as long as there is a "public school" system, I don't think vouchers are the solution. The problem is that, although you say, "no strings attached," it's very hard to have government money without strings. The experience of colleges in this matter is very instructive, as is the experience of "virtual schools" - public school at home - in various states. Once they give out the money, they begin making demands.
In a situation where there was no government school system, with its vested interest in expanding its funding and number of employees, a voucher program might be more conducive to genuine freedom in education. Still, philosophically, I favor private pay or private charity. Americans are generous people, and when they are allowed to spend their own money, they will do it both more productively and more charitably than the government does.
If we could eliminate Federal, state and local government from the education business altogether, our taxes would be cut dramatically. Local and state by 50%. So then the education consumers (parents, students) would have the CASH in their pockets to make choices without any government voucher system at all.
A starting point would be offering your county's school "business" to private education companies. (This industry would grow fast.) They take over and bill parents. Sell school buildings to either the education company or other investors, with lease back to education company. Eliminate county and state school-related taxes, which are huge part of current real estate tax bills. Cut sales taxes, get rid of all government employees associated with these schools. (Many would probably get jobs with private companies.) An example of this is already happening, in part, as Kelly Education Services takes over substitute teacher "business" in my area.