My ST just passed the 150K mark with few problems. My adventures with the thermostat are well chronicled, and a definite problem and poor design. Otherwise, mine has been good. I had the transmission fully serviced at 85,000 miles, and so far it has been good. Probably time to do it again, keep the fluid fresh.
It is also used as a tow vehicle for my Cobra race car, the trailer and car weighing in right round 3500 lbs, the limit of the truck. I tow with a light foot. I get 16-20 MPG on the highway, depending on speed, and around town 12-16.
Mine is a Job 2, and loaded with all the options, but a fabric interior. Love the rubber floor mats.
It does eat tires. Changed the shocks. I would not consider taking mine off-road, the 4.0 V-6 just does not have any real grunt.
My .02
BTW - I just ordered the KaleCo "O-Pipe" in hoping to get a better exhaust tone and increased performance.