Yep, had a ST TDCI for about a year now. Tbh, I can't fault mine.
Don't expect amazing mpg but i normally average 42-45mpg (about 500 miles to a tank). It'll do 50mpg on a nice quiet 70mph motorway run but more like mid-40s if you stick with the fast lane drivers. Good torque, and handles well for a big car. Little crashy over the bumpy stuff but then its a bit stiffer and lower than most diesels so you have to expect it in return for the improved handling. I'm still happy with the ride on my commute which is all B-roads (or worse).
Interior is nice, half leather. Miles ahead of Subaru
The uprated Sony audio system is very good, heated seats nice in the cold, plus heated front screen defrosts in a couple of minutes with even the heaviest frost.
Problems wise.... lot of talk on the web about injector issues but touch wood, no issues with mine. EGR valves fail after getting clogged up (can put car into limp mode) but the part can be bought from Jag dealers for ~£140 and is easy to fit. Nothing else has gone wrong on mine other than the battery giving up, car has done roughly 85k. If you get one, expect the wheels to need a refurb as the factory finish is poor and doesn't last long. Most people get them refurbed in normal paint rather than the shiny chrome finish (whatever its called).
Generally, a quick comfy diesel. I've been thinking of selling mine for a legacy (just fancy a nice legacy estate) but the Mondeo also ticks so many boxes boxes that i haven't made the jump yet. You're welcome to pop over if you want to go out in it/have a look.