I switched on the 5GHz band all compatible devices and let the oldest on the 2.4GHz band. In both cases, the gain is significant: on my Sony VAIO to really light Wifi reception, I increased the rate by 2 near the terminal (effective 200Mbps WiFi n) and 5 on the lower level ( effective 100Mbps).
The interface is fairly intuitive. I do not comment myself on advanced functionality (router, printer sharing and USB storage media) because I have not tested them. Too bad that the manufacturers do not offer simple as efficient access points without all the additional features at lower prices. This remains an important investment for the average Joe who just seeks to boost its box Wifi (often disastrous).