I'll second that.
Good input from everyone on this post.
I've got 35,000 miles on my '09 800GS.
Finally arrived at the combo that works best for me.
Most of my long trips are 7,000 to 10,000 miles.
Combo: Front - Anakee 2's (for 80/20 riding)
or TKC 80's for more of a 50/50 riding split
Rear - Heidenau's K-60's (no question asked)
I put 11,000 on the first rear and that included over 3000 miles being "extreme" off-road up in Oregon.
I pulled it off to try the Conti- TKC's out and the Heidi still had 2 to 3k mile left on it. Easily!
Recently tried the TKC 80 on the back and was toast after 3500 miles of tarmac riding. In all fairness
the TKC's on the rear was damn good in the off-road portion. Very stable and secure feeling. Just no life.
(Yes I am a bit on the heavy side, 225 lb and I do always carry all my camping gear on these trips.)
I've tried the METZLER Unicross All-Terain on the front, and I was happy as heck with it. That was until I hit a tarmac "ledge" a bit too hard and resulted in a pinched tube kind of a blow-out. (Went down pretty good that day.)m Good tire for off-road, but maybe the side walls could be stiffened a bit.