More info from IRC...

He claims that punin defined "unit" as not being the full 400 Gh/s in this post.
I disagree; punin admits the single board did not meet expectations, but he never says the ordered unit won't. On the contrary, he says an additional board will be provided to make sure the delivered specs are met.
It seems to me two boards comprise the full unit of this "first batch".
Not the advertised design, but it does meet the advertised specs the bet mentioned.

Furthermore, he also admits that he made this bet after he though the conclusion was certain (ie, reading that post), and that he was not prepared to lose.
Betting when one is certain of the outcome is morally wrong unless the other party agrees knowing you are certain.
This can clearly not be the case for everyone who bet before the forum post in question.
So, I'm not at all sympathetic, as he basically tried to steal from the other betters.

While I still wouldn't recommend trusting mircea_popescu (who runs bitbet), he clearly made the right decision in this case.