I completed one Challenge so far, the July 4th one in Jacksonville. Probably a mistake since it was my third time actually doing a ruck. That said, it was an absolute blast, and kicked my ass in the best way possible, I just wish I didn't have to go straight home and onto work afterwards.. I'm lucky in that headquarters is less than two hours away, so there are plenty of events locally. I want to go do more, but change in employment has left the fun money bare for a bit, and looking like Uncle Sam will give me some free rucking experience in the next few months. As for the gear, it looks like it will go through hell and they have an amazing warranty to back it up. But my broke ass still can't justify spending and real coin on a pack, as it was I was the guy with a molle frame pack, which was an absolute mistake. You want something light that you can get on and off easier/faster.
I highly encourage everyone to try at least a light at some point, just make sure to prepare for it, it will wear on you. The cadre are all legit former or active sf and the few I've met were great. It's a great community and I hope to be able to go again soon. They are also starting a rucking 5k soon, and I'm hoping I can make that before my ship date.