as for me i was not think that pos is better then pow, but lastly i read i article from vitalic the co-founder of eth about why pos is better then pow, which his article was not really neutral , but it made me re-think about pos and starting researching and discovered that attacking pos with 51% attack is hard like attacking pow, and pos have super less energy consumption add to that they will make eth 2.0 can handle more transaction for next generation.
With PoS, with more ETH you have, the more power you have over the network. Think about it. If someone has a huge business and that people pay them a lot of ETH, they will automatically have significant power over the network because of that alone. It's one of the biggest flaws of PoS in my opinion.