I had a 900C for decades, it's apart now, but also have a 1000C and an 1100F. The F bike is a sportbike, like the 900F, but faster. It's fun in canyons and the fastest in it's day, but nothing like current sportbikes.
Between the 900C and 1000C, I really preferred the 900C. I didn't leave it stock for too long, I ended up with all the motor parts out of an 1100 motor in it and added Megacycle cams, and MSD ignition, and Smoothbores. It was a handful. That was in the 80s and 90s.
I did tour around on it, and I must say, if you want to go anywhere, the big Customs (the C in 900C is for Custom) are MUCH better than the Fs. My Customs are dressers, so they are suitable for traveling with the Interstate fairing and luggage. I used it to commute on and get groceries too. Let's see you do that on a random 900F. I wouldn't really care to have a 900C without the fairing and luggage though, it's not a great as a sportbike. It does take a bit of nerve to keep up with the guys in the canyons.
The 2 speed behind the regular 5 speed was maybe kind of an OBTW gimmick, but they needed a jackshaft to get the output of the motor to the other side of the bike so they could use the Goldwing rear end. While doing it, they added an overdrive ratio which is nice for cruising, and still keeps the real low first gear ratio. I gives a nice spread of ratios available without building a new tranny. And since with a shafty, you don't just change sprockets to get a whole new range, it actually worked well enough. In 1st low, it really jumps out of the hole, even with all the fairing and luggage on it... even more so with over 120hp from a hot-rodded 1100F motor.