Cardano is a blockchain-based ecosystem using a currency of the same name (ADA) as a fuel. It is regarded as one of the third-generation blockchain platforms. Currently, Cardano can be used to host smart contracts.
EOS is one of the most popular blockchain-based ecosystems hosting DApps, smart contracts, etc. The company held one of the longest ICO campaigns in history. It lasted for almost a year.
One of the selling points of EOS is the potential to develop a near to infinite scalability and cheapness. So far such scalability is yet to be achieved. The transaction fees can be reduced to zero through staking EOS.