Strava does a good job of recording ride routes and elevations. The average speed is pretty close to my cycling computer the vast majority of the time. Wattage has always been more of a crap shoot. I can ride the same bike, on the same route, at very close average speeds and often have a 25-30% variance in power estimates. On a few occasions, like yesterday, the readings are all over the place. The segment in question from yesterday is pretty short, just a couple of miles long, so that may be part of the reason. I'm not too concerned as if I wanted accuracy I'd get a power meter, but it still strikes me as funny that Strava can input and record the same bike, rider weight, location, elevation, and speed but still come up with such a wide variance (almost double) in power estimate. Maybe I'm just not tech savy enough, but it would make more sense to me if one of the input factors was significantly off, but when you start with the same numbers, why wouldn't you get the same answer?