Don't know about range, but if your main concern is speed on 5GHz., the AC model should connect at 433Mbps on 5GHz., as opposed to the 2x2 wireless-n model at 300Mbps on both 2.4 and 5GHz.
My desktop has a 1x1 wireless-AC adapter, connects at about 150Mbps on 2.4GHz., and 433Mbps on 5GHz.
Of course, the actual throughput that you get will be less than the connection speed, and that needs to be measured at your place *smile*.
I generally use external USB adapters, and have one (Asus USB-AC56) that connects on 5GHz. at 867Mbps, fine for me. I use 5GHz. as much as possible, so having a wireless-AC router is great.