I've been using nothing but Tourances on my GS's for about 12 years..... At least a dozen pairs in that time.
I did a run to Morocco a couple of years ago and had a set of Heidenaus fitted in Spain the night before arriving in Africa. They were very impressive in gravel, sand and mud...
But I have nothing to compare them with, as it was my first time off Tourances. All I know is, I would have binned the bike at least a dozen times if I'd tried the same terrain on Tourances.
I did aout 2500 miles on them.. Basically just Morrocco and then home.
Though Spain, France and Ireland they were ok, no issues, but not the same feedback as the Metzelers.
My lasting memory was when I was less than 10 miles from home, returning from the big trip, got a bit cheeky and realised I was doing 80 or 90mph on the Westlink towards the M2 into that nasty off camber left hand bend in the wet. The bike was fully laiden with a very chunky rider, enough luggage for a family of 4 including camping gear and spare parts. My nerve held out for cheeky lean angle on the Heidenaus in the rain and the bike never moved at all.
I changed the bike back to Tourances as they were already bought and waiting for my return.... The Heidenaus were donated to another member of the forum looking something for a bit off offroad, so I don't know what they were like in the mileage department.
I would say my riding is also 90% road and have another couple of months before I need new tyres. But I have recently found a wee bit of a playground where I may be able to enjoy the other 10%. I dont think I will be getting the regular Tourances next time. I'm torn between the new Tourance Next tyres or another set of Heidenaus.