Both Netflix (NASDAQ:NFLX) and Amazon (NASDAQ:AMZN) are fantastic companies with bright futures. They've already created a ton of wealth for investors, and both have tons of growth left in their tanks. If you own one of them but not the other, go ahead and fix that error right now. Those who own neither should really pick up both. The only way not to win is not to play, if I may paraphrase WarGames.

That said, there are some significant differences between the two FAANG companies. You may very well have a reason to prefer one over the other.

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The case for Amazon

Sporting a market cap of $1.58 trillion today, Amazon is one of the largest companies in the world. The e-commerce and cloud computing giant collected $348 billion of top-line sales over the last four quarters, holding on to $24.7 billion of that haul in the form of free cash flows. Amazon is a cash machine. You should expect all of these impressive numbers to surge even higher when the company reports fourth-quarter results in a couple of weeks.

The law of large numbers implies that Amazon should run out of rocket fuel someday soon. Doubling your sales should be much quicker and easier when your current results are smaller, and growth rates should generally slow down over time. Well, Amazon has found ways around that mathematical dilemma over the years.

CEO Jeff Bezos famously wants Amazon to treat every day as the first day of operations at an up-and-coming start-up company. His company is taking that ambitious approach seriously. There always seems to be another growth-boosting move just around the corner. From next-day delivery and the Whole Foods market buyout to the rise of Amazon Web Services, Amazon's ideas rarely miss the mark. Here's how Amazon's top and bottom lines have been skyrocketing in recent years:

AMZN Revenue (TTM) Chart

AMZN Revenue (TTM = trailing 12 month) data by YCharts

Next up, Amazon is beefing up its domestic delivery network even further and exploring an enormous target market in international e-commerce sales. The company launched a local store in Sweden just three months ago, for example. Amazon will ship to nearly every corner of the world, but is only operating 19 local shopping sites. It's a great big world out there, and Amazon should be able to continue its skyrocketing growth for years by expanding its global reach.

The case for Netflix

Netflix took that global plunge five years ago, launching its video-streaming services in nearly every country all at once. At the same time, the company boosted its commitment to creating Netflix originals rather than relying on content under license from other studios. Annual sales more than tripled over the last five years, while annual earnings skyrocketed from roughly breakeven to $6.20 per share.

NFLX Revenue (TTM) Chart

NFLX Revenue (TTM = trailing 12 month) data by YCharts

Like Amazon, Netflix is still aiming for high-octane growth in the long run. The company is adding subscribers at breakneck speed while also raising its monthly subscription fees. The media-streaming market is still young, and Netflix is in a prime position to grab the lion's share of this centennial business opportunity.

Unlike Amazon, Netflix has picked a narrow market niche and intends to dominate this market for years or even decades to come.

"We are not a generic 'video' company that streams all types of video such as news, user-generated, live sports, porn, music video, and gaming. We are a movie and TV series entertainment network," Netflix's long-term view document states. Other ideas may pop up later, but Netflix is all about winning the global battle for viewers of movies and TV series.

The coronavirus-based content production stoppage in 2020 had the unexpected side effect of proving to Wall Street that Netflix can turn a solid cash profit at the drop of a hat. What started as a tiny DVD-rental-by-mail operation in 1997 has expanded into a global media giant and one of the most productive content studios on the planet.

Netflix is shooting for maximum subscriber and revenue growth at this point. I can't wait to see where the $223 billion market cap is going when the company decides it's time to optimize the bottom line instead.

The winner: You

Amazon is exploring massive growth opportunities in international e-commerce, cloud computing, and a constant search for brand new business ideas. Invest in Amazon if you believe that the global economy will continue to embrace internet-based retail and cloud-based services.

Netflix may have found a smaller target market, but the company is poised to dominate subscription-based online video services nearly everywhere. Bet on Netflix if you believe that there will be room in most people's budgets for a high-quality media service at a reasonable monthly cost, and that the media-streaming market will benefit from wider access to high-speed internet services and reliable options for digital payments.

There is absolutely nothing wrong with owning both Netflix and Amazon. Both have been crushing the market for many years and should continue to do so for the foreseeable future. You really can't go wrong with owning these fantastic companies.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.