Which smartphone is stable these days?

janimal writes: It used to be true that the iPhone was the smartphone that "just works". Ever since the 4S days, this has been true less and less with each generation. My wife's iPhone 6 needs to be restarted several times per week for things like internet search or making calls to work. An older 5S I'm using also doesn't consistently stream to Apple TV, doesn't display song names correctly on Apple TV and third party peripherals (like a Mercedes Benz). In short, the mainstay of Apple that is quality is fast receding. In your opinion, which smartphone brand these days is taking up the slack and delivering a fully featured smartphone that "just works"?