It's a little weird to see an Evo cat take down SoH in one to two hit crits. That mage must have had really low MA because some powers take two or more hits with elementals while using Guard Break.
I can't be exact with this though since every mage has different MA value.
Like zgmfx09a said, Evo isn't the best option in pvp. If you are ever in a competitive duel, the reduction of HV can be deadly towards you.
Getting Evolution is more of a grinding skill / aesthetics.