Well crap... I have two C7s. IMO there might not be (or at least have been) a better mainstream router for the price.
I think it’s a bit extreme to say the C7 is the best. It never was the best performer, and already 802.11ac Wave 2 devices with MU-MIMO are on the market, potentially outperforming the C7. Maybe it’s coincidentally the best value for the money, but that will not last.
Every generation, I wearily observe the large number of router models. I thought the Buffalo WZR-600DHP was a pretty good value late in the 802.11n generation, but now it’s retailing for more than I paid for it. WiFi routers are a lemon market.
I suppose people will start rooting these devices. It's not like consumer routers have particularly impressive security track record.
Perhaps that's the way it should be, they come insecure by default and you're supposed to exploit that to enable installing your own, more secure, software...
When these die or get obsolete I think I'll finally just move up to the entry level business products a la Ubiquiti or the like.