So, as soon as I preordered my 6 Plus, I upgraded my wireless router to a new flagship 802.11ac model. Problem is, there's no way to prioritize wireless networks on the iPhone. And since the 5GHz AC signal range is shorter than the 2.4GHz N range, my iPhone always eventually moves from the AC network to the N network because the N signal is stronger. I was really hoping to take advantage of the AC speeds, but unless you're in the same room with the router (rarely for me), iPhone prefers the 2.4GHz band.