It's baffling to me how distant of a second it is in terms of popularity. Instead of forcing you to contort your program into a special paradigm in order to deal with reactivity in a sane way, it simply makes reactivity a non-concern (while remaining pretty simple and predictable when you do actually care to dig beneath the magic). You can write code in a way that's natural and simply not think about reactivity most of the time, and you'll even get better performance in many cases because of the highly-granular pub/sub that it sets up automatically. I cannot praise this paradigm enough.