If you had a time machine, there's no question which stock you'd go back in time to buy with a choice between Aphria (NYSE:APHA) and Canopy Growth (NYSE:CGC). Aphria has delivered a lifetime return that would have multiplied your initial investment more than 13 times. But Canopy Growth's share price has soared even more.

I'm going to assume, though, that you don't have a time machine. Choosing between Aphria and Canopy Growth isn't as easy without the benefit of hindsight. Which of these top marijuana stocks is more likely to be the bigger winner in the future? Here's how Aphria and Canopy stack up against each other.

Marijuana leaf in a shopping cart.

Image source: Getty Images.

The case for Aphria

Aphria has been through the wringer over the last few months. The company faced allegations that it drastically overpaid for its LATAM Holdings acquisition. Its CEO stepped down. Aphria even had to fight off a hostile takeover attempt. But you could make a pretty good argument that Aphria has emerged from all of this in better shape than ever.

While a special committee comprised of independent directors on Aphria's board of directors found that the company hadn't overpaid for its LATAM acquisition, one side effect of the investigation was that Aphria has improved its governance processes. The company also has a strong interim CEO in Irwin Simon -- who previously served as CEO of organic food company Hain Celestial -- while it searches for a full-time CEO.

Although Aphria's board rebuffed a takeover bid by U.S.-based cannabis company Green Growth Brands, the acquisition attempt helped draw attention to Aphria's strengths. One of those strengths is the company's production capacity. Aphria thinks that it will have an annual production capacity of 255,000 kilograms by the end of 2019. The recent licensing of its Aphria One facility expansion definitely helped the company in achieving that goal.

Aphria has supply agreements in place with all of Canada's provinces plus the Yukon territory. It partnered with Southern Glazer's, the largest wine and spirits distributor in North America, to distribute its adult-use recreational marijuana products across Canada. 

The company also has extensive international operations. Aphria is acquiring its German partner, CC Pharma, which distributes products to more than 13,000 pharmacies in Germany. It owns one of seven cannabis import licenses in Italy. Aphria owns 25% of Australian medical cannabis producer Althea. The company has a joint venture in Lesotho. And there's the LATAM Holdings acquisition, which gives Aphria access to medical marijuana markets in Colombia, Argentina, Jamaica, and possibly Brazil.

Aphria's historical sales don't justify its market cap of around $2.4 billion. However, the stock trades at a discount to several of its peers when you factor in Aphria's production capacity and growth prospects.

Check out the latest earnings call transcripts for the companies we cover.

The case for Canopy Growth

Canopy Growth's story has been a much happier one than Aphria's. The biggest development for Canopy was the massive $4 billion investment by alcoholic beverage giant Constellation Brands (NYSE:STZ) last year. This deal came less than a year after Constellation bought an initial 9.9% stake in Canopy Growth.

The relationship with Constellation Brands gives Canopy Growth two key advantages. One is that the company is flush with cash. The other big advantage is that Canopy has a partner with a successful track record in launching and building commercial brands.

Canopy and Constellation plan to launch a variety of cannabis-infused beverages later this year, pending the finalization of regulations governing the cannabis edibles market. Meanwhile, Canopy Growth is already the top player in the Canadian recreational marijuana market with industry-leading sales in the first quarter in which adult-use recreational pot sales were legal in the country.

Like Aphria, Canopy Growth has supply agreements with all of Canada's provinces. Canopy is contracted to supply a minimum of 70,000 kilograms of cannabis per year -- and that doesn't include Ontario, which has the largest population of any Canadian province. 

Canopy Growth is also a top player in international medical marijuana markets. The company has subsidiaries or stakes in companies in 13 countries, notably including Germany, Brazil, Colombia, Australia, and the United Kingdom. Canopy intends to use some of the cash from its deal with Constellation to fund additional expansion efforts in Europe and South America.

The company is also using some of its cash to move into the U.S. Although Canopy can't operate in the U.S. marijuana market and retain its listings on major stock exchanges, doing business in the U.S. hemp industry is a different story, thanks to the U.S. legalization of hemp in late 2018. Canopy Growth is investing between $100 million and $150 million to build a large-scale hemp production facility in New York state. This move makes the company an early leader among Canadian marijuana producers in entering the potentially lucrative U.S. hemp market.

Better buy

On a pure bang-for-the-buck basis, Aphria wins over Canopy Growth. Aphria's projected production capacity is roughly half that of Canopy Growth, but its market cap is less than one-sixth the size of Canopy Growth's market cap. 

However, Canopy Growth's relationship with Constellation Brands is a huge plus, in my view. The deal puts Canopy in the driver's seat for expanding globally. I also think that it's only a matter of time before the U.S. relaxes its federal marijuana laws, opening the door for Canopy (and Constellation) to jump in headfirst and likely emerge as a major force in the U.S. market. 

So which of these two marijuana stocks is the better buy? It depends on your time perspective. Over the next year or so, I suspect that Aphria could outperform Canopy Growth. Over the long run, though, I think that Canopy Growth is more likely to be the bigger winner.

Sure, the current valuations of both stocks (and especially Canopy Growth) look steep. But if global marijuana markets grow like many project they will, both Aphria and Canopy Growth could have a lot of room to run.