Whats happening is traditional blockchain is that one node can participate in only one consensus of blockchain at a time. This means entire computational resources of a node can be used for only one blockchain. MASS differs from this traditional approach by allowing a node to participate in consensus of more then one blockchain at a time by using storage space and this is huge add-on to efficiency of nodes.
MASS no doubt has many advantages over blockchains like Etherum and Polkadot. But we to see that MASS is in its very early stages of development. Right now its development period is more like the first phase of Ethereum.