Seriosuly, very hard AI is awesome if you play standard zerg, I think it's probably low/mid-diamond level if you don't abuse it's weakness. It scouts you, do a good army composition against yours and macro AWESOME
What i found out so far, the best race to pratice against is protoss as zerg it doesn't act anywhere near as a real zvz(no banelings) and terran don't abuse all the cheese that it can.
Did anybody pratice or had any good experience playing the AI? It's seens way above wc3 level.
Insane AI isn't really playable as you have to abuse it's weakness to win or maybe a close(maybe that's not even enoght) to perfect macro game and use some strategy you wouldn't use on an online game.