During the talk, Andreas spoke about the possible 51% attack -- reading between the lines without too much detail I think he was referring to an example .... the ETH fork not too long ago and how the ETC supporters bought all available Dagger-Hashimoto hash from NH at premium and throw hash at the ETC network to catchup with ETH network.... Vitalik was in the audience and ... Andreas didn't go any further on that discussion - but yes, I get him, I think when push comes to shove BU supporters will probably raid all available SHA256 hash for rent from NH to overtake SegWit fork. So when that happens, I dont mind selling my hash at premium. Call me opportunistic but WTH man... I am really sad if BTC comes to this stage.

According to Andreas, if the 51% attack happens -- there is only a "7 block" advantage and.. guess who has the hashing power stashed away in the Mongolian desert.

GPU mining.... hmmmm.... I think we are looking at a new "Trustware" platform, and it will certainly be GPU minable because software+hardware convergence although will be fair for all (and as predicted by Phil... so many hardware vendors will benefit vs only Bitmaintech profits).... it will not repeat the BTC's case of Bitmaintech dominating ASICs hardware. This is just my opinion. I am taking a big bet on ETH mining since, adoption by major exchanges and Coinbase already favors ETH. So I think ETH is safe haven for now at least short term until POS in 2018. I wonder is  ETH is the benchmark of a "Trustware".