I've got an early pair of T8s, fantastic boot, but heavy. 9 years and 35,000 km, 2 resoles and I've lost count of the number of insteps replaced, which is a great feature. Dunno why, but I wear out the left instep at a rate of 3 or 4 to one compared to the right, which means that I've got plenty of spare rights if any one wants any.
Got a great deal, and therefore a new pair of T8s, as yet unworn, but they are hugely changed, and heaps lighter compared to my old ones, so time will tell how they go compared to the oldies. I'll swap sometime, but they still fit like an old pair of boots, and still protect, although not all that waterproof. Shoe Goo, and silicone lube do wonders for longetivity..
I'm not sure how easily the T10 style sole can be replaced by your average bootmaker, which may limit their ultimate life.
Cheers
Steve