Many investors overlook mid-cap stocks, partly because they're not as financially stable as large-cap stocks and partly because they're not growing as quickly as small-caps. But mid-cap stocks offer a mix of both - solid growth and financial stability. If you don't want the hassle of investing in individual stocks, you can gain exposure to mid-cap stocks through an ETF.

A mid-cap ETF is an exchange-traded fund that invests in the market's mid-size companies, where the total value of the company's stock ranges from a few billion dollars to $20 billion or so. Mid-cap ETFs are a great way to own the companies that are growing quickly and have good financial stability without having to analyze individual stocks and picking the winners.

The mid-caps include plenty of companies that you haven't heard of as well as quite a few that you may use in your daily life. And the best of the mid-cap stocks will continue to grow larger, ultimately becoming large-caps and multiplying your initial investments many times over.

Mid-cap companies may be popular with investors for a few reasons:

Those are great positives for investors, but if you have no interest in investing yourself and don't want to do the legwork of research and analysis, a great place to begin is buying a mid-cap ETF. (And here are the best small-cap ETFs and best large-cap ETFs based on their overall returns.)

Bankrate selected its top funds based on the following criteria:

This passively managed fund is based on the S&P MidCap 400 Pure Value index, which includes stocks in the S&P MidCap 400 index that score well for value characteristics such as low price-to-book value, low price-to-earnings ratio and low price-to-sales ratio.