It's hard to believe that just a few years ago, investors were worried that Starbucks (NASDAQ:SBUX) had seen its best days. This worry has been all but eradicated, as the company has posted strong revenue and earnings growth for multiple quarters. Though the stock is up more than 13% from its lowest point this year, there are at least three reasons to believe investors can still make bucks with Starbucks.

Worldwide brand appeal
Starbucks has been a worldwide brand for years, but the current quarter gives us the first reason. The company reported strong global same-store sales growth of 6%. Relative to its peers, Starbucks is in a league of its own.

Dunkin' Brands (NASDAQ:DNKN) is another company that makes a lot of money selling coffee, among many other items. Dunkin' also carries worldwide appeal, as it has thousands of Dunkin' Donuts and Baskin-Robbins stores worldwide. However, the donut chain is operating in the slow lane relative to Starbucks.

In the last several months, Dunkin' Brands' domestic Dunkin' Donuts same-store sales increased by just 1.2% annually, and the division's international comps actually declined by 2.4%.

Though Keurig Green Mountain (UNKNOWN:GMCR.DL) is a Starbucks competitor, the two companies have found themselves partnering to release Starbucks beverages on the Keurig system. Since Keurig Green Mountain doesn't report same-store sales, the comparison by total sales growth makes more sense here.

In their respective earnings reports, Keurig Green Mountain and Starbucks reported sales growth of 10% and 9% annually. However, in the last fiscal year for each company, Starbucks' total revenue equaled almost $15 billion, whereas Keurig Green Mountain managed about $4.3 billion in annual sales. When you consider that Starbucks was able to almost match Keurig Green Mountain's growth rate at more than three times the sales, you can see the power of the brand.

Sometimes bigger really is better
The second reason investors can make bucks with Starbucks is because of the bucks Starbucks makes (try saying that three times fast.) Starbucks is a free-cash-flow-generating machine. In the last six months, the company generated roughly $1.3 billion in core free cash flow (net income + depreciation - capital expenditures).

This is a situation where yet again Starbucks leaves its competition in the dust. Keurig Green Mountain has been primarily focused on investing for growth in the past and over just the last few quarters has turned its attention to free cash flow. The company did produce almost $300 million in core free cash flow in the last six months, but relative to Starbucks the company just can't compete.

Dunkin' Brands also generates free cash flow but again at a much smaller amount than Starbucks. The company produced slightly less than $50 million in core free cash flow in the last three months. Even if Dunkin' Brands tripled its free cash flow, the company would still produce nearly $1 billion less in free cash flow than Starbucks in a six-month period. Apparently in the coffee business, bigger really is better.

I'd like to order a tall glass of fizz
While Starbucks is one of the current kings of coffee, the company clearly isn't comfortable sticking with just coffee. Starbucks acquired La Boulange to expand its bakery selection. Later that same year, the company acquired the Teavana chain, effectively telling the world it wants a bigger share of the tea business.

The third reason investors could make bucks with Starbucks comes from the company's next growth product, handcrafted sodas. Starbucks is testing sodas called Fizzio that come in ginger ale, lemon ale, and root beer.

If Starbucks can convince consumers that buying handcrafted sodas is worth the extra expense, this could be a huge new market for the company. The carbonated- beverage industry is expected to produce worldwide revenue of more than $200 billion in 2014. If Starbucks took even just 1% of these sales, it could add more than 10% to the company's annual growth rate.

As you can see, Starbucks has strong worldwide appeal, and the company generates huge free cash flow. Combine these traits with new potential share of the worldwide tea and soda markets, and you have a company that could make big bucks for shareholders indeed.