The AirPort Extreme is going to win when it comes to simplicity and reliability. In 2013, for my Eagle Scout project, I deployed twelve AirPort Expresses (2nd gen.) and an Extreme as the central router in my high school. This system handled 150+ clients daily with all traffic being routed through the Extreme. There was never a speed issue or any problems with reliability. In the process of going 1:1 for the entire high school, we now use an AirPort Extreme (6th generation) as the main router with UniFi access points. Even with loads of sometimes 200+ bandwidth hungry clients, the Extreme handles it perfectly.
We have an Extreme at home and it has never once given us an issue since installing it over two years ago and neither did the fifth generation before it. The performance is great and it offers quite a few features like official Time Machine support and also comes with a great warranty. Each one has a one year warranty but if you have AppleCare on an Apple TV, Mac, or iPad, then the AirPort is covered if it is purchased up to two years prior.
In benchmarks, the AirPort is not going to perform as well as flagship routers from Netgear and ASUS. That being said, in the real world I have never experienced any performance shortages with any AirPort. In the end, if you want a router that you can buy, setup, and forget about then the AirPort is your perfect match. However, if you want every conceivable setting available to you and the highest benchmarks then the ASUS line is your better bet.