Bitcoiin is a cryptocurrency that was created to address some of the issues that have plagued the original Bitcoin ecosystem. It's Proof-of-Work (PoW) consensus mechanism is designed to decrease transactions times and fees, as well as make mining rewards easier to earn.

Mindexcoin is developing a universal payment platform powered by the Ethereum based token, MIC. Their marketing materials do not clearly outline any unique selling points, or advantages, that it will provide compared to other blokchain-based payment platforms.

Viacoin is an open source cryptocurrency based on the Bitcoin protocol. Viacoin has a 24 second block time and relatively fast transaction times. It can handle 175 transactions per second without scaling through Segwit or the Lightning Network. The fast transaction times make Viacoin a good option for sending micropayments. The platform also enables users to perform cross-chain atomic swaps between different cryptocurrencies, without a centralized exchange. Viacoin has an Auxiliary Proof-of-Work (AuxPoW) consensus mechanism that allows miners to mine multiple coins, that use the Scrypt algorithms, at the same time. Viacoin's smart contract platform, Rootstock, is compatible with Ethereum smart contracts.