My 2006 ZX4 SES has been extremely reliable. The only problem I've had was the left front exterior door handle snapping. $35 in parts and about an hour and a half of my time. I've got almost 100,000 miles on it, had it for a year and a half with no big problems at all.
As matmatician said the Focus has been a pretty solid car since the end of the SPI engine. The launch of the DCT transmission in the Focus was as much an engineering flop as it was a lack of knowledge about the transmission and its operation. Not many people understood that it was two 3-speed manual transmissions put together and shifted automatically. Therefore, people were not ready for the vehicle to transmit power the way it was. That being said, there have been many updates for smoother operation of the transmission as well as improvement of the My Ford Touch system, across all vehicle lines.
I lessthanthree my car