Sometimes I find that while people like some ads, Google shows them rarely and favors other(s).
I also find that with Rotate we have more insight into what people would really click onto (by comparing CTR for ads that show on same spot) - until Google sinks some of the ads.
Thanks
I personally set all campaigns to rotate and then after some decent impressions I knock out the under performing ads.
The other factor in favour of rotate is that optimize works towards CTR whereas what most people want is conversion rate - if you find an ad that has high CTR and conversion rate then great, but you don't want to cull high converting ads just because they are lagging behind a poor converting, high CTR ad.
i rotate when i need datasets that are equivalent to one another, to test ideas where each permutation gets the same exposure.other than that, i'm on optimize 99.9% of the time, allowing G to show what they think is best.
Exactly what I do as well.
Moreover, even if you set them to rotate, if one ad appears to be doing *significantly* better than the other(s), Google will go ahead and show that one more often anyway.
Half the strategies/advice you find in these forums differ from vertical to vertical so take everything with a grain of salt. Maybe try to search for SEM advice particular to your industry, just don't use specifics because people really hate that around here.