PoW works nicely in p2p settings, from small clusters to Internet scale. However, at Internet scale over a long period of time not clear sustainable model.
PoS not suited for small p2p settings below some monetary threshold t. At Internet scale threshold t becomes easily surpassed, just need to ensure a relatively “fair” distribution.
Peercoin does PoS consensus with PoW distribution.
2nd layer solution could be PoW consensus (PrimeCoin 1 minute blocks) with periodic PoS blocks as anchors for proof of ordering.