You know what - Ive been experiencing similar issues.
First all devices were cutting out intermittently. Then I checked and checked and checked, reset reset and reset and within a week or so, the 5GHz band was alive and working fine *fingers crossed* (well i think it was that - pretty sure they weren't working properly before)
Now, my apple devices are just dropping every so often, I've checked and seen that they are on the 2.4GHz band, so maybe it is that issue. Now Im not sure what to do.
Do I disable 2.4GHz - will my apple devices connect at all, Do I change the wireless mode? or should i disable channel optimization?