The place to check the ratings on 529 College Savings Plans is www.SavingforCollege.com. They rank programs based on performance and costs, and over one-year periods and longer. It’s hard to say which is the “best’ for your situation, because if you live in some states (like Illinois) you get a state income tax deduction for a portion of your contribution. But right on the home page of this site, you’ll find a search box that asks for your state of residence and promises to find the “best” fund for your situation. Remember, tax benefits accrue to you based on YOUR state of residence. And no matter where the grandchildren live, they can use the money for a college in any state.