I currently have a 4th Gen AE. I feel like I am not getting good speeds downstairs. (This is prior to and after upgrading to Yosemite) I can get a 5th Gen off of Craigslist for 75. I can get a 6th Gen off of Craigslist for 150. I am sure the 6th gen will get better speeds at greater distances. We do have a few ac devices (iPhone 6, Macbook Air). I am trying to get better Wifi without spending too much money.