My focus was totaled a couple of months ago, I chose to go with the Mazda and I've been very happy with my decision so far. After doing a ton of research on both cars I just was not too thrilled with the issues Ford has been having with the latest Focus and while I enjoyed my previous Focus, it certainly was not without issues. I drive a lot and already have almost 15k on the Mazda with zero issues. Drive both for a decent amount of time before you decide, they both have their strengths and weaknesses, personally I liked the suspension/steering in the Mazda much better but I will give the nod to the Focus in the looks department.
Good luck with your decision.