That's 5" of mush, rated for 400lbs of riders. The front axle is a 20mm bolt on, and the discs at the time were 203mm titanium. The frame and most of the smaller hardware are titanium too. There was a bit of a learning curve, but for tandems, it's mostly trust and communication. The captain needs to call out bumps and obstacles to the stoker. I don't recall a single crash on the trails - it actually handled really well.
The only sketchy situation we were ever in was actually on pavement, riding down a very steep hill. We exceeded the speed limit by a big margin, and I was losing faith in the brakes. In corners, the tires would squeal like a Starsky & Hutch police chase.
When I brought it in to show the guys at our local downhill shop (this was in Australia, and it was the guys from Phoenix Films) one of them commented that he would just want duct tape over his goggles if he had to ride out back.