Would have considered 3 secs block time a joke if announced by someone else other than dero developers.
3 seconds block time with 500 TPS is much bigger achievement to everyone in industry not just for dero.
BitShares has 2 secs block time and proven 3k TPS with 100k TPS theoretical.
Dero is POW and on private CryotoNote chain. Bitshare is DPOS and public chain.