I stopped using them last week, but only because I was turning my hash power toward monero pools. Good thing too.
sounds like this was a honeypot that someone probably had access to for some time, but were waiting for the market to go high enough before making their move.
I'm sure some will speculate that it was an inside job, where those in charge took their money and ran, using the "ermagerd, we were hacked!" excuse, but I don't believe this is the case. I don't have evidence either way and don't care to speculate myself.
Hopefully no one had their savings in there or something. Not smart, but then again who would think nicehash was that vulnerable?