It seems like this is the ad everyone wants to talk about at the moment, so in a way, that means it 'must' be good.

But personally, I'm conflicted. Although I love all things 80's, and can certainly appreciate an array of beautiful women, I'm less keen on sexism.

Does the fact that it's set in 1984 make it okay, in the same way that the sexism of Mad Men doesn't indicate a prejudiced writing staff, but rather a desire for authentic period detail?

Not really. Mad Men critiques sexism. This ad celebrates it.