The biggest I found is that PoS is more complex and less tested.
Is there already a fork of Bitcoin that used PoS? I would like to see how it does.
So yea, PoS is the way to go, at least wrecking the environment is not incentivized as much.
- PoS is more complex than PoW. This means that it is more likely to have security vulnerabilities that have not been discovered yet. - PoS gives an unfair advantage to early adopters, the wealthiest users. Those who have a lot of coins will have a much higher chance of validating blocks than those who have few coins. This likely lead to centralization of the network. - PoS is less secure than PoW. In a 51% attack [0], a malicious actor would need to control more than half of the coins in order to have a chance of validating more than half of the blocks. This is much harder to do than in a PoW system, where a malicious actor would only need to control more than half of the mining power. - PoS could lead to inflation; if the price of the coin goes up, then those who have a lot of coins will be able to validate more blocks and earn more coins and could cause inflation if not properly managed.
Maybe the most important argument against it is that proof of stake requires users to have a certain amount of money staked in the network in order to validate transactions. This could lead to centralization if only a small group of people have enough money to participate in the validation process. Second, proof of stake coins typically require users to keep their coins locked up for a period of time in order to earn rewards. This could also lead to centralization as it would be difficult for new users to join the network and earn rewards.
The problem with Peercoin for example, a fork of Bitcoin using PoS, is that it relies on checkpoints - the blockchain blocks that have been verified by the network's nodes and agreed upon as the most recent correct blocks. So it's quite centralized.
In a PoS system, users will use pooling to avoid staking themselfes.
In a PoW system, much fewer actors will mine in the first place. And those who do will either be very big or use pooling too. Afaik, just a handful of Bitcoin mining pools hold over 50% of all Bitcoin mining power.