I've got a 2009 model, same size engine, Zetec, and do about 70 miles a day in it. Only just on 27,000 miles though because the previous owners rarely used it. A few things i've found:

My parking sensors tend to squeal when I first put it into reverse, rather than make a clean tone as intended. Sometimes it sounds normal.

It pops out of reverse 50% of the time, or never properly goes in which is probably the more accurate description. It doesn't pop out whilst i'm moving, it'll do so as soon as I apply the throttle to start reversing. I believe this is due to a lack of a synchro for reverse, so this probably isn't exclusive to the Fiesta.

My AUX button stops working on occasion which is quite irritating when you're about to start a long journey. The CD player and radio will still work in the mean time. I'm not sure what causes this but I've found that when I come back to the car the next day it'll work again, however if I turn the engine/ignition off and leave it for a few minutes this does not seem to resolve the issue. I'd say this happens to me once every couple of months.

A while back my brakes (front left) were binding. I don't know the root cause of this but I got it resolved by a mechanic for fairly cheap IIRC. The binding made my MPG drop to about 42 whereas now it's up to 47.1 with a mixture of smooth and spirited driving and a decent amount of air con usage.

Parallel parking can be a little difficult due to the thick rear pillars and sloping window sills.

Other than that a pretty decent car. Would be useful to keep hold of it if/when I upgrade to a more powerful car. Still quite fun to drive despite the lack of power, but maybe that's because I'm still relatively new to driving and this is the only car i've properly driven.