NextGen Investing: Check out these alternatives to Robinhood

Millennials have been dubbed "Robinhood investors" because so many have opened accounts with the online brokerage. Robinhood said it had snapped up more than half of all new brokerage accounts opened last year. And a recent survey found the average age of a Robinhood investor is 31. With its gamified interface and no-fee trading, Robinhood has disrupted the once-staid brokerage world.

But Robinhood is not the only option for young investors. Other brokerages have had excellent online trading platforms for years. E*Trade, for example, which much like Robinhood disrupted the brokerage world when it launched in 1982 with low-commission trading, offers a robust platform with far more portfolio information than Robinhood. And traditional brokers such as JPMorgan Chase, Fidelity and Charles Schwab offer online platforms with no-commission or low-commission trades.

Each online brokerage has its strengths and weaknesses, depending on your investment goals. Robinhood is great for speedy buys and sells and offers a large range of investment types, including cryptocurrencies. Others, such as Fidelity and Charles Schwab, have better advice for those with a long-term investing strategy typically used for retirement accounts. For those who believe in a buy-and-hold strategy, commissions are less of a consideration because you will be trading less. And some investors like to do due diligence before investing, so the amount of research materials available for free is important to them.

Here are three resources you can check out before choosing an online broker:

Investopedia has a comprehensive guide with a deep dive into fees and a look into how brokerages differ based on investment strategies.

StockBrokers.com has a useful guide to online brokers on its website. Its top choice for beginners is TD Ameritrade.

And NerdWallet has an evaluation of the 11 best online brokers. NerdWallet also likes TD Ameritrade the best.