One hill which I'm on frequently, Strava thinks that my rides are 240-290 watts going down hill, and 180-200 watts going up. But I'm taking it easy on the descent, coasting parts of it, and killing myself on the return uphill. My weight is entered correctly, myself and my bike. I could fudge the weight to make it come out more reasonably, but whether that's really where Strava is miscalculating who knows? Regardless, the power estimate is way off.