If you, like me, have issues with frequent disconnects on Windows 8 on Cisco WLANs, you may try disabling Fast Roaming and Radio Management Support under Cisco Options in PROSet. With those enabled my Windows 8 with Intel 7260-AC Dual Band couldn't keep a ping going for more than 60 seconds (Windows 7 puzzlingly don't seem to have an issue either way). With them unchecked I could walk around the office, roaming between 6 different WAPs, without skipping a ping. YMMV.
It actually was enabled in the driver bundle I downloaded from Dell for the Latitude E7240. For other models I've noticed that those options are deselected by default, so might have been a slip-up for that particular download only.