Although NiceHash is usually regarded as a mining service, it's better to say that it's a kind of a platform for selling/buying cloud mining contracts. What is special about NiceHash is that users can opt for both selling and buying the hash power on this platform.
MoneroHash is a US mining pool created solely for Monero mining. Since 2014 it is run by a single person. The fee is 1.6 and a part of this amount is given to open source developers. The payouts occur every 24 hour (in case if the threshold is reached). There's an option to send the mined coins straight to the exchange wallet. It saves users some money that could be spent on transaction fees.