Proof of Stake currencies can be several thousand times more cost effective.

Proof of stake is used to deter other service abuses such as a Sybil attack.

Nxt - Cryptocurrency financial platform that uses proof of stake to reach consensus for transactions.

But Proof of Stake advocates believe most described attack scenarios are impossible or so unpredictable that they are only theoretical.

Proof of Work or Proof of Stake ?

Crypto assets can be protected in different ways: by proof of stake or proof of work or by a mixture of both these systems together.

Reddcoin's 'Proof of Stake Velocity' (PoSV) claims to encourage velocity i.e. movement of money between people, rather than hoarding.

On August 23, Potcoin changed mining algorithms from Scrypt to POSV, a proof of stake algorithm designed to reward not only the ownership of coins but also transactions.

BlackCoin's Proof of Stake system secures the protocol through an efficient, decentralized process called "minting," while Bitcoin uses a mining process that has been well documented as expensive and energy-intensive.