College is more expensive than ever, and it takes foresight to prepare fully for the financial burden of paying for a college education. Students collectively have taken out about $1.2 trillion in outstanding student loan debt, and that overhang has financially crippled many graduates for years after they leave school.

Parents can help by saving toward their children's college costs, and many people -- including me -- use 529 plans to get some valuable tax benefits from college saving. Being able to save in a tax-favored account has a number of advantages, as Fool personal finance expert Maurie Backman notes in this article. Indeed, 529 plans were just expanded to offer tax benefits for savings toward pre-college educational costs as well. But there are a few problems with 529 plans that make incorporating alternative methods of saving for college look more attractive. Here are three reasons to consider going beyond 529 plans for your college savings.

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1. Limited investment options

The biggest reason why you might want to go beyond 529 plans is if you're an investor who wants to go beyond the limited investment choices that you have in 529s. Typically, you'll be limited to mutual funds, ETFs, and various bank products like certificates of deposit in a 529. That's fine for many people for whom a good index fund is enough to reach their financial goals. But if you want to invest in individual stocks, you'll be out of luck.

By contrast, some alternatives let you have much more flexibility in your savings. Coverdell Education Savings Accounts allow for full brokerage options, although one barrier there being a low $2,000 annual contribution limit. Some savers use Roth IRAs as a way of saving on a tax-deferred basis, with the intent of taking out contributed amounts tax-free when needed for tuition and other educational costs. Even a regular brokerage account can be a decent alternative, especially if you intend to buy and hold individual stocks. You'll still have to pay tax when you sell, but you'll defer it for years along the way.

2. High costs for some plans

There are dozens of different 529 plans, and not all of them are created equally. Some good 529 plans use low-cost index funds that have rock-bottom expense ratios. They'll never match the even lower costs that you could get on your own outside a 529 because the sponsors of 529 plans inevitably add their own fees on top of what the investment managers charge.

Where things get particularly bad, though, is with states that insist on using high-cost investment managers. You're not required to use your own state's 529 plan, but some states offer tax incentives that are only available if you stay in-state with your college savings. That can put you in the unfortunate situation of choosing a bad plan to get a tax break or to give up the tax break to get into a better plan. Making an informed decision on that front is a lot to ask from parents struggling just to get enough savings to set aside for college.