I have two laptops with the iwl-7260 card in them, one is a Dell E7440, the other a Lenovo T540p; the former runs openSUSE 13.1 x86-64, the latter Ubuntu 14.04 x86-64, and both dual boot Windows 7pro-x86-64.
Both suffer the same wifi drop problem, basically stop sending and receiving packets, it's a lot worse with Windows
The solution is to drop the connection entirely. It's quite annoying, and as someone says if you're doing long-running file transfers (not necessarily big files if the server is slow), particularly when using windows, you really have to do it over cabled network as wifi will let you down!
This is very annoying, and I have frequently pondered sending a formal complaint to Intel and asking them to loan me indefinitely an older non 802.11-ac card which doesn't suffer the problem, until such time as they fix the 7260ac firmware, because the product is basically defective. It would be interesting to know if Apple have used this card and if it has the same problem.