I'm liking it so far; rapidly approaching 2,000 miles on my Focus with PowerShift.
I haven't had any problems. There was a bit of shudder under moderate acceleration when it was very new, but it's quite smooth now (I'm guessing that was the clutches wearing in).
Upshifts are very smooth. Since the dual clutch system provides continuous power to the wheels, shifts are barely noticeable. If not for the change in engine output and note, and the drop of the tachometer needle, you'd barely know it was shifting at all.
But I do feel that it upshifts too quickly in regular (D) mode. It's only a little better in sport (S) mode. It seems that the best way to prevent early upshifting is to mash the throttle down... which is not the greatest thing for your fuel economy, ofc.
In sport mode, it downshifts when you hit the brakes. In fact, it downshifts fairly aggressively throughout the braking process. Very cool. This usually leaves you in a much better gear for exiting a turn than regular mode does.
In D, it's usually a gear (or two) too high after completing a turn. To get it into an appropriate gear requires a heavy foot and a wait for a downshift (or two).
Another thing it does in sport mode is delay upshifts after hard acceleration. This is not nearly as cool as the downshifting under braking. In fact, I don't like it at all. I can see where it might be good to have on a track... but I drive on public roads, haha.
With a normal automatic, when if you accelerate hard to, say, 50 MPH and then let off, the transmission immediately shifts to the highest available gear and the engine very quickly settles down.
With the PowerShift in sport mode, after a hard romp to 50 MPH and then letting off the accelerator, it does not immediately upshift, but rather holds the lower gear for a moment longer (in case you have second thoughts about ceasing acceleration, I guess). This can leave the engine revved up quite high at a time when you think it should be quieting down (you took your foot off the gas, after all). You also get quite a bit of engine braking going on until it finally decides that you really are done accelerating and upshifts.
In regular mode, it behaves exactly like a traditional automatic transmission, immediately upshifting a gear (or two, or three, as needed) when you let off the accelerator.
6th gear is locked out in sport mode, unless you use the plus-minus button on the shifter to get it into 6th gear... but this will put the transmission in manual shift mode. Sport mode does tend to settle into a gear that's a bit lower than when in regular mode. It seems to keep the engine around 1800-2000 RPM, while regular mode will shift into 6th gear at quite low speeds, practically lugging the engine. This is great for fuel economy, but rather annoying when you need to accelerate a bit.
Another rather disconcerting thing (at least the first couple times it happens), is a tendency to roll backwards briefly when moving off on an incline. Never more than a couple inches, though. Not really a problem, just a little reminder of the true nature of the transmission.
I've also noticed that it's sometimes necessary to give the throttle a little goose to get the car moving, especially in reverse. (This could be because of my driveway... a rather haphazard collection of concrete slabs of varying dimensions and horizontality.)
And you can forget about hard launches. No clutch-dumping allowed. You just have to wait for the transmission computer to fully engage things before you get full acceleration. I can't blame Ford for not programming the transmission computer to abuse the drivetrain... but just a little bit harder take-off would be welcome.
The plus-minus button the shifter is a bit of a joke, in my opinion. Shifts seem very slow to come after pushing the button, and it only works in sport mode. And once you press it, the transmission goes into 'manual shift mode' and the only way to get it back into regular or sport mode is to move the shift lever to D (and then back to S if you want automatically shifted sport mode.)
Overall, I think it's a good system. Shifts are smooth and operation is predictable, albeit slightly different than a traditional automatic. 'Sport mode' could use some tweaking. Fuel economy is outstanding. If the longevity is there, it's a winner for sure.