Re: "Proof of Stake alone is considered to an unworkable consensus mechanism"?
Hi JG! 
Had to Google that. I thought you were talking about Josh Garza at first.
All serious research into POS has shown that "Nothing at Stake" is the bogey man that POW/Bitcoin Maximalists use in in fear tactics.
This may have been possible for the earliest POS coins, but newer, solid implementations have nothing to fear. That is what the research says (5-6 full research papers with statistical models are available for those who want to go neck deep into the specifics):...
...This research is specifically into Nxt's POS mechanism. If unsure about your POS coin, ask your dev what POS implementation it is based on.
This may have been possible for the earliest POS coins, but newer, solid implementations have nothing to fear. That is what the research says (5-6 full research papers with statistical models are available for those who want to go neck deep into the specifics):...
...This research is specifically into Nxt's POS mechanism. If unsure about your POS coin, ask your dev what POS implementation it is based on.
I know NXT and BitShares have their own PoS implementations but most PoS coins currently out there are based on Peercoin aren't they? And Peercoin was the first implementation of PoS.
To be fair, if you read the rest of the article then it's actually not at all negative about PoS. It even speaks quite positively about it in the "Motivation for Proof of Stake" section. That one sentence stands out and isn't really expanded upon, as it only appears to have been added in the most recent edit.