Just above the article will give you slightly better CTR but I still believe that Adsense doesn't love this. Not that its against the TOS persay but if they manual review your site and aren't crazy about it then this type of placement may be an issue.

I place all of mine inside the article, at the beginning, and on the right. The performance depends on the niche and how targeted the content is to the ads. I have some sites that perform at 10% using this method and I have others that only perform at 2%.

Also, make sure you are using a link unit at the top of the page where a menu would be. I place mine right below my regular navigation menu. For years I avoided using the link units, but that was a big mistake. I get about 30% of my revenue from link units.

I think the CTR is generally higher when you put it above the article. But you can always split test it. Try it above the article and run it for a few days and check your CTR. Then try it on the left side for a few days and check the CTR.