Almost every currency software has a different intended purpose and individual implementation, with inherent strengths and weaknesses.
It's like Windows vs Mac.
…or iOS vs Android.
Here are a few examples of the different types of cryptocurrencies and what they are designed to do. This is not an exhaustive list, just a sample.
Worldwide Financial Transactions
Bitcoin
Litecoin
Tether
Ripple
Stellar Lumens
Application Platforms
Ethereum
Storj
Siacoin
MaidSafe
Private Financial Transactions
Monero
Dash
Zcash
Specialty Currencies
GameCredits
ReddCoin
Take a look at these different use cases and figure out which ones make the most sense to you. Then understand how each software implementation works and think about what will probably do well in the future.
This is SIMPLY is the way to know which Coin(s) to BUY and HOLD for the long term profit.