I was running TKC 80 front and rear on the 950.. For me it wasn't better than the stock Scorpions offroad:( (sand + gravel) It was a major disappointment for me.
It was OK onroad, but the rear wears faster than the scorps, plus on the road I always had to worry about the speedometer, not to overshoot it's speed rating (Q - 160km/h) + it's scarry on wet tarmac. I would never buy them again..
I don't know how it performs in mud, but as I've read it's not a champion there as well.
I'm using Michelin Desert on my 640, and I'm in love with that tire (off road and dry onroad).
If I wear out the current (scorpion mt90) set on the 950, I'll try the Deserts on it as well, or maybe the Pirelli Scorpion Rally is, that looks quite promising to me as well.
2005.5 950 Adventure (with 265mm travel suspension