As many discussed here before - there two type of FA - merit based and need based. None of PYH give any merit based aids. So, if your children are good students and could get into PYH. The decision is then purely based on your income. If your income is above the need base line, you will pay the full amount. Under this situation, saving into those accounts may save you some taxes.
If your income is not that high, every penny you saved will be counted toward your contribution. The more you save, the more you have to pay. So, instead of buying a Ford and put saving into an education account, you should buy a Mercedes and enjoy life now.
On the other hand, if your children can't get 2400 SAT and 800's on SAT II and 15 or more 5's in AP, your better save some money for them to go to Other" universities. Soon it will have to take that much for a Chinese to get into PYH, IMHO.