Strava gives no additional information, other than calculating power, over Garmin Connect. It has a different presentation, for instance, you can overlay cadence, heartrate, elevation and speed graphs - that's pretty handy. But, overall, other than the "social network" aspect and some other minor differences, it's very much like Garmin Connect. It's free, so give it a try - RR was my impetus to use it (and she doesn't know it - well, she does now!).
Tomorrow - 100 plus miles are planned. Here's hoping I can finish this ride on my bike, and not in an ambulance!