Image source: Fitbit.

With a market cap approaching $580 billion, Apple (NASDAQ:AAPL) is more than 190-times larger than Fitbit (NYSE:FIT). Apple pays a healthy dividend, derives the overwhelming majority of its revenue from smartphones, and trades at a modest 12.5-times trailing 12-month earnings. Fitbit pays no dividend, sells no smartphones, and trades with a valuation more than twice as rich.

Nevertheless, the companies are competitors, and in many ways have similar business models -- both firms attain the majority of their revenue from consumer electronics. Investors looking to add exposure to the space might be drawn to consider one of these two stocks.

Apple is a technology stalwart -- and, increasingly, a value stock

Apple's days of rapid growth appear to be over. The company's sales contracted 15% on an annual basis last quarter, with iPhone shipments posting an identical drop. iPad sales rose modestly, but Apple's tablet business has been in decline for most of the last two years. The Mac business remains steady, although it too declined last quarter. If analyst projections prove accurate, Apple will generate about 8% less revenue in its fiscal year 2016 than it did in the year prior.

Nevertheless, Apple has proven to be a solid, albeit unremarkable stock, in 2016. It's outperformed the broader market, but not to a significant degree, rising just over 6% year-to-date.

The gain may have been driven by Apple's increasing preeminence as one of the best value stocks in tech. Despite the recent decline in iPhone shipments, Apple's smartphone business remains resilient in the face of intense competition. Its services business is improving (sales rose 19% on an annual basis last quarter), and it's returning more capital to shareholders. Apple currently yields just over 2%, and management has promised to increased its dividend each year for the foreseeable future.

In contrast, Fitbit's business is growing rapidly

What Apple's current management team hasn't done is release a revolutionary new product -- at least not anything on par with the iPhone or iPad. For a time, it appeared that the Apple Watch could be Apple's next breakout hit, but demand for the Cupertino tech giant's first wearable has proven to be relatively lackluster. Shipments of the Apple Watch fell 55% on an annual basis last quarter according to research firm IDC.

Fitbit's wearable business, in contrast, is dominating. Fitbit remains the world's largest seller of wearables, capturing almost one-third of the market in the first quarter, according to IDC. To be fair, most of Fitbit's trackers are considerably cheaper than the Apple Watch, but that may be part of their appeal.

Fitbit's revenue has been growing rapidly in recent quarters. Sales rose more than 100% annually in 2015, and are on pace to grow about 35% this year. To date, Fitbit has sold fewer than 50 million trackers, giving it ample opportunity for further growth, particularly overseas, as most of its sales have been to consumers in North America.

As a stock, Fitbit has performed poorly since it made its public market debut last year -- shares are down about 50%. Investors seem skeptical of the company's long-term success, believing that ever-more-powerful smartwatches, including the second- and third-generation Apple Watch, could erode the market for Fitbit's comparatively less complex trackers.

But if that doesn't happen, Fitbit could reward shareholders. Fitbit stock isn't cheap, but it trades at a sizable discount relative to its growth potential. At around $14.80, Fitbit is currently trading with a forward price-to-earnings ratio around 10 -- less than Apple's.

Fitbit is a pure wearables play with a greater degree of risk

For investors looking to add wearable exposure to their portfolios, Fitbit is the better stock. Just about all of its revenue comes from its wearable fitness trackers, and it continues to lead that market. Apple, in contrast, has emerged as a key player over the last years, but the Apple Watch remains a modest driver of Apple's financials, and that may not change anytime in the near future.

Fitbit, however, appears to carry a far greater degree of risk. In the worst case scenario, demand for Fitbit's trackers could fall to almost nothing in the coming years as consumers adopt more fully featured products from companies like Apple. It's far less likely that the iPhone will suffer such a fate.

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.