I also have the STT's and have about 8000 miles on them.
The tires don't seem to wear down too fast.
They have fairly good road manners -for a mud tire- and they're
not too loud.
The tires see about 80% pavement and 20% offroad.
On snow they do fairly good but on icy roads they suck as
much as every other non-studded tire. They loose sideways grip on snow and ice fairly easy and suddenly, so go easy on curvy roads unless you intend to play.
A few no-no's what I've experienced are wet grassy dirt hills and clay. Clay really clogs up the tire and makes it like it was made of ice. Wet grassy dirt hills: my HJ61 didn't have a chance going up a little hill even with front & rear axle locks on and it wasn't even steep.
I really like the tire for everyday use for it's good all-around manners. Change the tires front to back, side to side about every 5000 or so miles, and you have yourself a good set for a long time.
Mine are also 33x12.5x15 and I'd buy a new pair again.
Hope this helps a bit.