When it comes to investing in cryptocurrencies, I've taken a go-slow approach ... as in, a glacial, watch-the-paint-dry-and-the-grass-grow pace. Because new tokens hit the market all the time, and Bob's Bitcoin or Charlie's Crypto can become overnight superstars merely because they're available, it makes me leery about diving in.

For example, we all know that Dogecoin was created as a joke, but somehow, it's up 4,300% in 2021 -- even though its co-creator Jackson Palmer says cryptocurrencies have no value and generally hurt the average person who buys them.

Shiba Inu dog

Image source: Getty Images.

Yet fear of missing out -- aka FOMO -- often causes people to rush into trades that end up hurting their finances, sometimes severely. The momentum in the cryptocurrency market, no matter which token in particular one is talking about, seems tailor-made to elicit such reactions.

I, on the other hand, am beset not by FOMO, but by FUD -- fear, uncertainty, and doubt -- when it comes to the long-term viability of digital currencies. All that said, though, there are a few cryptocurrencies that do have value and seem promising. These two look to have the greatest chances of handily outperforming for investors over the coming years.

Cardano ADA coin

Image source: Getty Images.

Cardano

The fifth-largest cryptocurrency globally by market cap (though it's a very fluid, fast-changing number), Cardano (ADA -2.12%) has a fast network, a blockchain architecture that offers adaptability and scalability, requires less energy to mine than its rivals, and charges lower transaction fees. 

What strikes me as especially attractive -- beyond the transparency of its developers -- is that it was peer-reviewed, data-driven, and developed with a team of engineers and academics. That kind of pedigree, plus a methodical approach to development, minimizes its volatility.

While that can work against it to a certain extent -- for example, it was slow to introduce smart contracts, or self-executing, programmable agreements -- it reduces the odds of screw-ups. 

Having implemented its "Goguen" phase, which brought smart contracts to the fore, Cardano will focus next on the "Basho" phase of development, during which it will upgrade the scalability of its network by introducing sidechains that won't degrade its security. That will be followed by its "Voltaire" phase, when its developers will concentrate on sustainability with such additions as voting and treasury systems, which are essentially decentralized decision-making mechanisms for funding blockchain development and maintenance projects.

Proposals are put up for a discussion and voted on by the community with those ranking highest getting funded. It's a bottom up approach ensuring that what the community thinks is a priority gets funded from the treasury.

While ADA, Cardano's native cryptocurrency on the blockchain, has pulled back from the recent record highs (even as other coins have surged), Cardano's carefully mapped-out strategic plan suggests it will eventually win converts and that it is a crypto that will be around for years to come.

Gold Ethereum coin held over Bitcoins

Image source: Getty Images.

Ethereum

Ethereum (ETH -2.59%) is the go-to blockchain infrastructure that Cardano seeks to displace. Though Bitcoin still has its first-to-market advantages, Ethereum is arguably the most established cryptocurrency because of its real-world utility and the potential for non-financial applications. 

Its blockchain is one of the most widely used when it comes to decentralized applications such as non-fungible tokens, or digital certificates of ownership. And where Cardano is just launching smart contracts, they're already an established feature of Ethereum.

Because of the robust nature of its infrastructure, Ethereum has become the platform most used by developers who are working on projects like decentralized finance. Its smart contracts allow them to complete transactions on financially focused blockchains and bypass traditional financial institutions.

Yet, while financial applications seem like the most practical and obvious use of blockchain technology, it is in realms beyond finance where things get really intriguing. The widespread supply chain disruptions we're currently experiencing could be partially relieved with the help of blockchain technology; under traditional systems, much of the data necessary to make supply chains work smoothly isn't always visible, available, or entirely trustable.

Real estate and healthcare are other areas where blockchains could be beneficial. In my view, the underlying technology is where the greatest utility lies, not so much in the tokens.

Still, while Ethereum has its faults -- mining it is very energy-intensive, and it has higher transaction fees than other tokens -- it continues to develop and incorporate improvements into its systems. Its planned transition from a proof-of-work mining protocol to a more environmentally sustainable proof-of-stake protocol suggests Ethereum will be able to maintain its premier status well into the future.