What about Bitshares's and Crypti's
DPOS 
There are a couple of differences, if I understand DPOS correctly:
1. A miner needs to trust a delegate in DPOS while a miner joins a stake pool in POR - there is no trust. A miner can monitor the pool and leave if the pool misbehaves.
2. The major difference is that ONE delegate signs a block at a time in DPOS while ALL pools sign each and every block in POR. This is critical b/c this allows detection of multiple voting and bad behavior of the pools. Is there any mechanism in DPOS to defend against N@S?
