Okay, okay, I'll give you my impressions of the cars.
Please keep in mind that my test drives were meant to be a study of how daily-driveable the cars were, not a performance test. IMHO, flogging new cars that you have no intention of buying is tacky. I trust the magazine reviews to give me an idea of how fast the dang things are.
That said, here we go. Please note, earlier in the day, I had driven a GTI, an Abarth, and a FR-S. I had to drive a ways to find a Fiesta ST in stock. The salesguy got my DL info, and pretty much tossed me the keys. The Fiesta is pretty tiny inside compared to my current daily driver, but the important controls were laid out well enough, that after a little fiddling with the seat, mirrors, and telescoping steering wheel, I managed to get in a comfortable position. Pulled out of the dealer's lot onto a wide four lane road, and the car had sufficient torque that you can easily upshift around 2000-2500 RPMs if you are loafing around. It rides pretty nice on smooth concrete, but then I turned onto a windy two lane. At that point, the voice in the back of my head started screaming "Buy this car!!!!" The ride was a little rough, but nothing abusive, and to use a trite statement, it handled like it was on rails. It didn't seem to ride any rougher than my old NC Miata. I managed to sit in the back seat, and still fit in it, I think it'd be okay for four people, as long as it is a short trip.
The closest car I've driven to this is a friend's Mazda2 Touring (which is a platform-mate), and it felt like someone had taken that car, sharpened up the handling, put in a great interior, then stuffed an engine that had actual power into it. As I told my wife, the Abarth was the kind of car that says "Let's go play in the street.", the Fiesta ST is the kind of car that says "Let's go knock over a liquor store." And this is even when I'm trying to drive in a responsible fashion.
The Focus ST was at a dealer close to home. I went out with a salesman in tow, and he actually directed me to a route that included windy two lane backroads, a four lane state highway, and an interstate. You can tell the Focus has more power on tap than the Fiesta, even at very low RPMs, and the ride was firm, but seemed better than the Fiesta's. I believe that had more to do with the extra weight and wheelbase, though, as it still handled great, with no signs of it getting out of shape at extralegal speeds on the two lane road. The car was perfectly competent, and still had a bit of the "hooligan" feel of the Fiesta, but definitely more grown up. Still not as mature as the GTI, though. It had noticeably more rear seat legroom and cargo space than its little brother.
I had one ergonomic issue with it, other drivers might not notice it, and I could probably get used to it. I sat far enough into the Recaro seat, that my arm kind of rubbed the side of the armrest when I reached for the shifter in a "natural" way. If I lifted my arm a bit, it went over the armrest and my hand hit the shifter just right.
In summary, if you are looking for a fun "family" car, or want the absolute best acceleration, the Focus is probably the one you want. If you don't need the space, don't mind the fact that it is a smidge slower, and aren't planning on going on long trips with passengers, the Fiesta is the winner