Buying high-quality growth stocks is arguably the most effective way to create wealth -- especially for investors willing to hold their stocks for long periods of time and let the power of compounding work its magic.

But actually finding the best stocks on the market isn't easy. So we asked three top Motley Fool investors to help out to that end. Read on to learn why they think Alphabet (GOOG -1.33%) (GOOGL -1.33%), Extreme Networks (EXTR -0.53%), and Camping World Holdings (CWH 0.85%) are three growth stocks worthy of owning for the long term.

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IMAGE SOURCE: GETTY IMAGES.

This is Alphabet's world

Steve Symington (Alphabet): Chances are, you've used an Alphabet product extremely recently. It's the holding company for Google, which claims seven products that each have at least one billion users, from Search to YouTube, Chrome, Maps, Android, Gmail, and the Google Play Store.

Thanks to that unrivaled suite of products, Google's core advertising business is still growing quickly as the digital ad market thrives. Last quarter alone, advertising revenue climbed more than 24% year over year to just over $26.6 billion, led by stellar performances from YouTube and improved monetization from mobile traffic. 

But even Google's non-advertising revenue jumped 36% to almost $4.4 billion, driven by its higher-margin cloud business, hardware products (think Google Home smart speakers and Nest connected home products), and its Pixel smartphones.

And that's not to mention Alphabet's "Other Bets" segment, which houses Waymo self-driving vehicles, Fiber high-speed internet, Verily life sciences products, and a handful of other high-potential, early-stage businesses. That said, most of these businesses are in their respective pre-revenue stages and still operate at a loss. But those losses are more than covered by Google's lucrative primary operations and should prove more than worth their while as they progress over the long term.

In the end, I think that makes Alphabet a growth stock worth owning for the foreseeable future.

Watch out, Cisco -- Extreme is coming up from behind!

Anders Bylund (Extreme Networks): The networking hardware market will surely remain relevant for many decades to come -- but the leaders in this sector may change. At the moment, industry veteran Extreme Networks is putting together a Franken-business out of smaller rivals, and the resulting end-to-end portfolio of data center networking solutions could pose a serious long-term challenge to sector leaders Cisco Systems and Juniper Networks.

Extreme Networks is hardly a new kid on the block. The company has been producing traditional Ethernet routers and switches since 1996. As wireless and fiber-optic alternatives matured into serious contenders, Ethernet solutions started to fall out of favor. So, Extreme picked up a handful of strategic acquisitions in the areas of wireless networking, networked storage systems, and virtual networking software.

The buyout binge kick-started Extreme's stalled growth in a hurry. Today, this is the third largest player in the data center networking market as measured by annual revenues. Management expects to see $650 million in data center revenue in fiscal year 2018, which ends in July. Cisco and Juniper can feel Extreme catching up from behind.

The company has some improvements left to do. Extreme's profits and cash flows sometimes turn up dipped in red ink and it may take some time before all operating kinks have been worked out of last year's numerous acquisitions. But in the long run, I like Extreme's chances of taking market share in one of the healthiest industries I know.

Starting from a rock-bottom P/E ratio of 8.8 times forward earnings, it's hard to go wrong with Extreme Networks shares at today's deep-discount prices. Company insiders are snapping up more stock, and I think it makes sense to follow suit.

Getting away from it all

Rich Duprey (Camping World Holdings): The continuously improving economy ought to provide a boost to recreational vehicle manufacturer Camping World Holdings, which benefits from an expanding GDP, low unemployment, rising wages, and improved consumer confidence.

There are headwinds it is facing because of the tariffs President Trump imposed on aluminum and steel from Canada, Mexico, and the EU, but CEO Marcus Lemonis is determined not to raise prices, and not to eat the higher costs that will come from it. He is looking for ways to lower costs in the manufacturing process to have the best of both worlds.

That puts him in a different position from his rivals at Winnebago and Thor Industries, which are actively exploring higher prices to offset their increased costs, and which could give Camping World a competitive advantage.

The RV industry has enjoyed eight straight years of growth, and it is expecting 2018 to be a banner year, too. Shipments are up 13% through April from where they were last year, and manufacturers are using their capacity to meet demand.

That was part of the reason Camping World bought outdoor sporting goods retailer Gander Mountain last year out of bankruptcy. It didn't want to get into big-box retailing -- rather it wanted more locations from which to sell RVs.

Camping World trades at a fraction of its sales as well as its long-term earnings growth estimates. At less than five times trailing earnings and eight times next year's earnings forecast, the RV maker goes for a significant discount against its peers. It also offers a modest dividend that yields 1.3% annually.

Trade policies and high gas prices could be a speed bump, but the longer-term health of the business seems better, and Camping World Holdings' depressed valuation suggests it will be a growth company that will offer substantial returns to investors for years to come.

The bottom line

We can't guarantee that these three growth stocks will continue to outgrow their respective industries, or beat the broader stock market. But whether we're talking about Alphabet's status as a diversified internet juggernaut, Extreme Networks challenging fellow network hardware leaders, or Camping World's cheap stock and competitive advantages in the RV space, we believe investors can do well by owning each of them for the long run.