Have a 2012 Focus as a rental right now for a couple of weeks. Have found that renting a car before buying one helps quite a bit. Would have to agree 100% with the comments about the jerky transmission; even a quick start from a stoplight can cause hesitation with the tranny. I love the gas mileage and the on board computer. Would buy one of these cars if it weren't for the transmission. FORD, please do something about this problem, and these things will sell like hotcakes.
If you love the gas mileage, it is probably because of the transmission. They do have hesitations here and there, as they try to run as economically as possible. I have noticed this in many different cars with electronically controlled automatics. You can always switch to a car with a CVT in it, and then you won't get any shifting jerks and hesitations.
If you don't like the jerky transmission, consider the "true" manual transmission. Many people don't consider them because they never learned how to drive one, but once you know how, they make the driving experience that much more fun. Manuals are cheaper to replace, and truly make driving a car a fun and engaging experience.
I first learned to drive a manual on an old Ford Ranger, and now both my Suzuki and 1996 Ford Mustang GT are manuals (the Mustang is a blast, and I wouldn't want it any other way).
Manuals are great on sports cars and fast cars, but in day to day driving with economy cars, they get tedious really quickly. You constantly have to shift due to the lack of power, and it gets old fast in traffic.
Also, nowadays more automatic transmissions get better fuel economy than their manual counterparts. The automatics have become so efficient, which is part of the reason they have certain hesitations in them. The computer is constantly compensating for load and vehicle speed to optimize the economy. If you are on a slight hill or giving it the wrong amount of gas, the transmission will misread the input. It can be annoying, but I find if you concentrate on it and learn when it does it, and change how you drive slightly, you can avoid it most of the time.
Another choice is the CVT transmission. They really outperform both the AT and manual trannys in performance and fuel efficiency.
I have a 2012 Focus. It doesn't have transmission problems, it's an automated-manual transmission.
I picked up a 2012 Focus Ti the first week of March this year, and haven't had any major issues with the automated manual transmission (DCT) or MyFord Touch.
My car was fresh off the truck with a manufacture date of 2/12/12, so it's possible that Ford has worked the kinks out of the transmission since these reviews were posted. Also, the MFT performance update had been installed by the dealer the morning I purchased it.
The 2012 Ford Focus is nothing short of pure awesomeness. I wouldn't even consider a different car in this class.