In addition to power, there is Normalized Power®, xPower, Pace (including GAP), Heart Rate, Cadence and VAM. If the athlete weight is known a running power estimation is available too!
The analysis page is an awesome tool by itself. Sauce builds on this page by adding unique data fields and giving you access to the raw data values. For running and swimming activities this page is un-hidden so you can do in-depth analysis regardless of the activity type.
If you own a Garmin device, you can create your own live segment files based on ANY activity and ANY athlete. And it even works for downhill segments!
This is my favorite tool in the kit. You can analyze any segment or section of an activity and study what power and weight requirements were used to achieve a particular speed. It works for time trials, hill climbs, and even downhills. I use this tool to estimate how many watts I'm going to need to increase or how many kilograms I'm going to have to drop to meet my goals.
Most settings are optional so you can turn on and off whatever you'd like.
Most people that install Sauce don't even realize the inline comments weren't done by Strava. It's otherwise wasted space in the page so why not put it there!?
01100100011000010111010001100001 like a boss
Sauce adds TCX, GPX and FIT exporting to any activity, not just your own.
FTP and weight, when available, are visible. Even when not available you can plug in custom values to activate stats like Watts/kg.