I have seen them in the flesh, and although they have a chunky tread they probably have more contact patch than a TKC80. Mileage speaking I have heard rears reaching 10,000 km, so about 6000 miles, and that was on an R1100GS that is both relatively heavy and relatively powerful.
Not bad in my opinion.
Back to the tread question. Admittedly the compound may not be as advanced as a bridgestone, but do you want a track tyre or a touring the back roads tyre. They are apparently fine in the dry, but should be ridden with reserve in the wet: common sense on any tyre in my opinion...
If I were to buy a trail style tyre, other than the K60, I'd prbably go for the Bridgeston Trailwing, or the Continental TKC80s, but we are still talking 20-75% more expensive at a guess...
Admittedly, tourances are said to last eons, but they are VERY expensive IIRR, and I did not feel very confident on them on my old GS: I ended up riding Michelin Pilot Roads.....
Adventure: it's an experience, not a style!
(so ride what you like, but ride it somewhere new!)