The 6th Circuit Court of Appeals has passed the 9th Circuit as the most reversed federal appellate court, says the ABA Journal.
Whether you view this distinction as a blot or an honor, if you're interested in such rankings you'll also want to see this SCOTUSblog post about reversals from the 2005-2011. Employing a "fuller" methodology of reversals moves the 6th circuit a few slots down on the reversal charts.