I am seeing similar issues.
My 2013 13" MacBook Pro, with AC, has no issues. But a 2012 13" MacBook air, with N only, as well as iPhone 5S, iPad mini, iPad 3, and AppleTV, have intermittent connection dropouts on 5Ghz. I would not say it is perfect on 2.4, but much better.
I switched over to 802.11a only based on the suggestions above. Not long enough to prove whether it fully works, but no dropouts far.