I've never used Dark Sky, but the most innovative weather app/site I've used is definitely Weather Underground. Their radar and 10-day view are second to none.

I've never used Dark Sky, but the most innovative weather app/site I've used is definitely Weather Underground. Their radar and 10-day view are second to none. It does sound like Dark Sky had one useful feature that has no match - analyzing weather radar and sending personalized rain alert push notifications based on your location. That's pretty awesome.