It typical for speeds to be lower over WiFi than connected via Ethernet and this router is no exception. The difference is that the loss of speed isn't significant with this router, even on a different floor in a different area of the house. I have the router sitting in the basement on top of my desk (right below an air duct) and the speed loss 5 feet from the router compared to the first floor is minimal, regardless of where I am on the floor. One thing that has confused me is that sometimes I get 200 Mbps speeds and other times I may get as low as 20mbps, despite the internet speed using the nighthawk speed test to be right around 200mbps. Maybe there is just a lot of 2.4 or 5 GHz congestion during those times? I also really enjoy that Circle is integrated and allows you to set up different devices to use different filters and set Google safe search and YouTube retracted. This is one thing that is lacking when using openDNS. Overall, excellent router after only a week.
I've had the router for about a week and its done a fantastic job both over WiFi and Ethernet. Signal strength is good and it is more than capable in handling my family's many devices.
I replaced an existing older system that was finicky and complicated to set up. This new item greatly simplified the complexity of my home networking setup and better manages the numerous newer devices appearing in my home.