Definitely get the 1.6 over the 1.4. It's still slow but it isn't dire, plenty around in Zetec trim with climate pack.
I've driven one before I got my 1.6 focus and it is waaay to under powered for a car of its size. To be honest the 1.6 I got was still under powered.
The 1.6 is enough for going A to B, you won't be beating much off the lights, but it serves it's purpose. Reliability is the key here.