My buddy posted this
Proof of Work (How bitcoin secures its blockchain, and how Ethereum currently does too but not for much longer) vs Proof of Stake (What ETH is migrating to now, and some other blockchains currently use). Here are a few high level points -
Pros of PoS:
- It uses 99.89% less electricity than PoW with a similar reduction in compute power required.
- It is more decentralized.
- It is a few orders of magnitude more secure. Resistance to hacks/51% attacks is much higher.
- It is a few orders of magnitude more censorship resistant (this refers to the ability for a government to shut it down. If the US or China wanted to destroy that blockchain, could they?).
Cons of PoS:
-There is a risk it can concentrate the asset over time. Bitcoin is so expensive to mine, that miners are forced to sell some of their bitcoin rewards to cover their overhead (electricity, cost of hardward, etc). Staking is so much cheaper that stakers can just hold on to the ETH they earn.
That con is more mitigated for ETH than other PoS chains because ETH was PoW for 5 years, then switched to PoS. So that first 5 years helped ensure a more even distribution of ownership before switching to PoS.
Some also think that is more of a theoretical risk than a practical risk because early investors tend to realize their gains as a token appreciates. We've already seen this play out. Most bitcoin bought in 2013 is not still in those same hands.
Also, on security - there are some key security risks to the bitcoin approach that ETH solved in a really smart way. BTC eventually will stop issuing block rewards once the full 21M BTC are issued. Then miners will rely on transaction fees alone.
Blockchains are more secure when more of the miner revenue comes from block rewards vs transaction fees. So how do you solve this without having a token that just inflates its supply over time? You always issue block rewards, but "burn"/destroy a portion of the transaction fees paid by the users. Starting in July, ETH will do this. At current transaction levels, ETH will have a shrinking supply. That bodes well for ETH price and the security of the ETH blockchain.