I had a FoST as a DD for about 7 months, but I put a solid 17k miles on it - my commute is 55-60 miles each way. I also had a Ford Racing tune done, which gave it something like 360lb/ft tq. For me, it was a love/hate relationship with the car. Mine was the ST3 trim, fully loaded. Things I loved about the car:
Torque. Holy torque steer Batman, this sucker goes!! From 2000rpm to 4500rpm it was a missile. Pulled like a freight train. That was great for rush hour traffic, as I could pull from any gear without having to constantly shift. Above 4500rpm was basically a waste of gas. Torque steer was bad, but it was FUN!!
Steering. Razor sharp. It went where you pointed it...right now.
Suspension. Handling was first rate (combined with steering), and ride was surprisingly compliant.
Recaros. Especially with heat. They were the bees knees.
MPG. - I averaged 28-30mpg, which for a vehicle this quick, isn't bad.
Things I hated about the car:
Requirement for premium unleaded. It is what it is, but when I drive this much, it hurts.
Turning radius. It needed more room to do a u-turn than a Kenworth. Royal pain when trying to park in a parking lot.
Hatch space. As noted by cmcgregor, it's not as big as you'd think. Plus the subwoofer took up even more space.
Ford TouchMyself system. Or whatever the hell it's called. I have mixed thoughts on touch screens anyway. This one had neat features when it worked, but it was prone to freeze up, respond slowly, etc...
The cars' "personality". My wife nicknamed it "Squirrel on caffeine", and that about sums it up. It always wants to go, go, go, which isn't a bad thing necessarily. But when you deal with a lot of stop and go traffic, it can get annoying. Don't know how else to describe it, it's just high strung and wasn't a happy camper creeping in heavy traffic (though darting into holes was fun).
I got rid of it partly because of those annoying things, partly because I wanted to spend my money elsewhere (wife), and partly because it gnawed at me that I was beating the daylights out of an expensive car. Would I get another one? Maybe. Honestly I miss the car in some respects. But the drawbacks were definitely not insignificant to me.