Edde after seeing where you crossed the Sahara on your K75 I would put that right up there as the most underrated travel bike.

So I am going to through the pro's and con's to the quad travel
Quad Cons
Thumb Throttle- must change out to twist throttle (that was our first mod)
Fuel consumption - 25 mpg (US miles and gallons)
Tires - have to plan ahead and have DHL deliver if traveling in the 3rd world.
Top Speed - only 50mph ( but we found that there is no need to do more than that in Africa, we were there to see the place so why fly by at 100 and miss it all)

Quad Pros
Storage - ability to carry 4 times more gear than a motorcycle.. my wife took all her camera equipment and now has signed a book deal. On a motorcycle she wouldnt have been able to carry the amount of gear she brought.
Terrain - the ability for a beginner to easily cross terrain that would challenge a Dakar Rally rider.
Novelty - on a motorcycle we couldnt get a magazine company to even talk to us, we were not famous moviestars with support vehicles, but on quads we write for 4 different magazines, in the end got a book deal and we even broke a Guinness World Record. *Diclaimer- we didnt do the trip for any hopes of fame or breaking records but it was nice to get the publicity while doing the trip.
Feeling - believe it or not you still get the same rush and feeling of the wind in your face and the sense of freedom that comes with a bike.
Safety - we did not fall over a single time, hitting dogs, chickens, pigs was never a concern. When we traveled in Mali on the BMW we had to miss some of the best countryside because we fell off the bike and hurt my wifes knee. But with the quads falling over in deep sand wasnt a concern.