With Bitcoin, there are quite a few completely independent clients available: https://en.bitcoin.it/wiki/Clients https://en.bitcoin.it/wiki/Clients, but the bea

With Bitcoin, there are quite a few completely independent clients available: https://en.bitcoin.it/wiki/Clients https://en.bitcoin.it/wiki/Clients, but the beauty of proof-of-work is that you do not need to trust any of them. With proof-of-work chains, one can download the blockchain even without a client and write a simple program/script to calculate the total work (hashes) embedded in the chain. This provides a completely independent measure of trust. With PoS, you must assume you can trust the client or root of the blockchain, which really kills the primary use-case of a decentralized currency.