Qtum has been described as a hybrid between Ethereum and Bitcoin. Qtum is a smart contracts platform that places a strong focus on value transfers as well as decentralized apps. Qtum enables users to create smart contracts on the platform and conduct cryptocurrency transactions.
Qtum has a Proof-of-Stake (PoS) consensus algorithm. Several decentralized apps are already using the platform.

Sharechain is developing a Proof-of-Work cryptocurrency platform. Their network is currently fueled by the Ethereum-based SSS token. Their marketing materials are unclear and do not offer any information about its advantages.