[Kiwi]

The obvious answer is probably true for all of us- FIRST has given me opportunities that I would never have otherwise had. Between music, drama, and languages there never will be any time in my schedule for shop classes. FIRST has been a hands-on learning experience in all sorts of useful things, from how to solder to the right way of building pneumatics to the vital skill of using power tools without killing oneself.
The most significant change in my life from FIRST has been my recognition this build season that computers aren't actually boring. (yeah... believe it or not, a mere six weeks ago I thought that code just sort of happened!)
If you join a team with an openminded attitude and the willingness to do whatever needs to be done, you'll learn more than you ever did in school-- and you'll only learn things that are interesting or useful!
Also, Team 847 PHRED is my sport. I dislike athletics because I find them totally arbitrary and not all that useful in the real world, but thanks to FIRST robotics I'm able to gain the experience of working on a team.
It's also a less militaristic way to meet interesting people. Nobody "normal" joins robotics, so it's a perfect place for the rest of us.