After the last update of WP to version 3.5.1 Quick Adsense begun moving the middle ad well down the page so that having also an end of post ad the two are just some sentences one from the other. Clearly this looks weird so I had to disable the end of the post ad and stick with only the middle one, which honestly is not anymore at the middle.
You can check it at http://www.ipnostudio.com on any post.
I tried almost every adsense plugin and nothing beats Quick Adsense also because it allows every ad code to be shown.
It would be also nice if instead of an end of the post ad it could be possible to have a "before the last paragraph ad" to work better if someone, as I do, uses a related posts plugin.
P.S. the support team at BuySellAds is great, they answered to my question the same day.