You haven't heard? Ethereum is going to be PoW. BitShares is DPoS , not PoS. Nxt is slowly dying and losing place to PoW and Debt based currencies.
There is no fundamental difference between DPoS and PoS.
Regarding Ethereum, here is the latest news -
https://www.youtube.com/watch?v=qPsCGvXyrP4. It says that Ethereum will be PoS.
DPOS makes the blockchain a lot more like a company than the wild west free-for-all of mining/forging that PoW/PoS entails. Block producers are not determined by the stake they own, they're determined by their reputation and trustworthiness in the community, and what they can offer in return for their block production (development, marketing, etc.). Like a mix between NXT and ripple if ripple labs was decentralized and run on the blockchain.
DPOS has no justification to make that claim. DPOS sells votes to the highest bidder. In politics that's called FASCISM. Unless you have a way to positively identify your voter registration, you will never have a fair election.