I've put almost 5000 miles on my focus.. other than a couple of PCM reflashes (one was an emmisions recall and the other was the poor throttle response TSB) I can't say i can complain other than the fact the Manual Trans don't like to be shifted fast... (gonna try the Mazdaspeed 3 rear motor mount swap to see if that fixes it...) if it does, then i'll have no complaints other than the fact Ford makes it very difficult to add higher trim level options to the base model after you've bought it. (Stupid Body Control Module...)
All cars have their issues and quirks.. The focus is no different... you can either live the issues that bug you, trade the thing off, or reverse engineer the design and fix the problems the right way to make it work to your liking...
I gotta give this focus credit tho, it's come the closest to being "correct" right out of the box, compared to the GM junk i've driven for years... In my experience the only way to get a GM car to work right is throw away any part with a GM part number and go aftermarket. The Focus on the other hand, doesn't appear to suffer this nearly as badly.