I'd definitely recommend the Asus RT-AC68U loaded with the latest Merlin firmware. Great range throughout the house. I use manual channel selection, and the InSSIDer tool on my laptop to find the best channels to use as auto channel selection by the router doesn't always get it right. Some channels seem to have a better range than others, depending on your environment.
Mine is placed at one end of the middle floor of my 3 storey town house. I get a good signal in all areas. Ideally I'd place it more centrally, but that's just not possible for me at the moment.