Traditionally, money has 3 functions:
- Medium of Exchange
- Store of Value
- Unit of account/pricing
Ripple (XRP) focuses on interoperability between systems, integrating with banks and other cryptocurrencies to reduce friction. They want to become the digital forex.
Bitcoin (BTC) focuses on store of value. The transaction fee & time is too high to be great for medium of exchange except for large purchases, e.g. currencies/expensive goods. In addition, BTC is the unit of account/pricing for most cryptocurrencies (you can only buy most other cryptocurrencies with bitcoin)
Some of the newer cryptos include smart contracts which enable the crypto to become a platform for applications and services. This greatly expands the utility of the currency in serving as a unit of account and as a medium of exchange. Ethereum (ETH) and Stratis (STRAT) fall into this category. Ethereum has first mover advantage. Stratis' value proposition is to allow people to write contracts in .NET and to make it easy for companies to run their own blockchains as a service in a side-chain for Stratis. They have a very ambitious roadmap and they are very early in development, but have a good shot at reaching a high % of developer mind-share.