motorhaven - 3:40 am on Jul 3, 2013 (gmt 0)
I have async working fine on the desktop. On my Android browser with a mobile skin the ads stack on top of each other where the last is on the page. I tried every combination of absolute, relative, clear, in and out of other DIVs, etc that I could throw at it, even went as fubar as wrapping it in a table.... 1st ad still stacked on top of the last ad.
So for now I'm sticking with the old code for mobile, but the new code is working fine on my desktop skin. Naturally YMMV depending on your template. Already scoring 94 with Pagespeed Insights with the mobile skin so it's not a show stopper for me to stick with the old for now.