I just got one a couple weeks back. Still testing out (iPhone 5s is still my primary, obviously). It seems very fast. The screen is beautiful. The camera leaves a lot to be desired, but apparently they’re trying to fix that through software. We’ll see.
Short answer: if you care about photography, you probably won’t want to switch back. Or if you use Verizon (which I do), you can’t. Otherwise, seems like a great device — best Android device I’ve used yet, though I haven’t had too much time with the Moto X.