I like $Apple(AAPL)$ because its shares have a long track record of rewarding investors. In fact, the stock has outperformed the S&P 500 by a wide margin over the last 10, five, three, and one year periods. A close look at the stock and, more importantly, the underlying business suggests there's likely more meaningful growth to come for Apple shareholders.

Apple boasts a powerful "engine" of loyal users. The iPhone accounts for over half of the company's annual revenue and is obviously imperative to the business.

But the real driver for Apple's business is the user behind the iPhone. The company's efforts to consistently deliver an integrated ecosystem of hardware, software, and services that delight customers have helped the company not just sell products, but also build a loyal base of customers across many actively used devices.

Pairing this installed base of active devices with the company's growing services business (sales from both native and third-party apps, cloud storage, AppleCare, and similar offerings), Apple boasts what management has been increasingly referring to as its "engine." An active base of loyal subscribers, which reached a record high in the company's most recently reported quarter, represents a monetization opportunity for the company as Apple works to increase customer engagement over time.

This engine gives Apple a reliable stream of revenue in its services business that will likely grow for the foreseeable future.