We had these tires installed last August on our work truck (less than a year ago).
We drive in the mountains, highway and city all in the same trip about 100 miles a day total.
The tires are about average as far as tires go, they are not great and not poor but the tread wear is unacceptable.
We do drive in various conditions including; rain, snow, mud, and hot summer asphalt roads, but we are past the wear bar on all four tires and only have about 22,500 miles on them. We are scheduled to take the truck to the tire shop early next week, and unless they honor the tread wear warranty and prorate the replacement tire's costs I will not be buying Firestone tires again.
We don't have a lot of extra weight in the work truck but its not empty either. I would compare it to an unloaded SUV in weight with two occupants (driver and a passenger).
If you live in the mountains or on roads with lots of corners the tread does not seem to last very long in our experience.
I don't feel like they are unsafe, but just an average tire that wears quickly.
I have Kumho Solus KR21 tires on my own personal truck (1994 Toyota 4WD Pickup, basically the same truck as our '90 work truck)and the Kumho's are almost 5 years old with about 30,000 miles on them and still have around half the tread left.
They are cheaper then the Firestones and comparable (average tires) but have better tread wear in my opinion, and I put them through the same exact roads and conditions as our work truck just not as often.
Someone else from our office left the tire choice to the tire shop based on our tire needs and the Firestone Destination LE is what they put on our work truck.