I too have the Firestone Transforce HT's on my 2008 Winnebago 31C. I had a set of Goodyears that lasted less than 2 years and 20,000 miles. Three of six came apart. One resulting in a blow out at 60mph. The other two had bubbles in the tread.
The Firestones ride great and track much better than the Goodyears.
I'm happy with my Firestone Transforce HT