Ashley is concerned about the "internet of things," where so many devices are internet enabled, and the router being able to handle so many connections. Leo says that most routers can handle 50-100 connections. So that's not an issue to worry much about.
Having said that, a dual band router does connect better. What's the best router to get? Leo says getting an 802.11 AC router, which can aim at the devices (called beam forming). Leo also likes open source routers like those that can run DD-WRT software. Asus is a good brand.