The 1.3 I believe is a bored out version of my 1.1 (older MK fiesta).
It is a terribly rattley, tappety and unrefined engine. Awful noise etc. However, they go and go and go, even when they're broken, they keep on going

For example, I drove the 164miles back from Loughborough Uni with a broken valve, so was effectively running on 3 cylinders. I did have to replace the engine about 6months after that though for the emissions at bang on 100k miles.
I get a bit over 40mpgand I rag the **** off it.
In essence, they're simple engines, cheap to fix, plentiful parts and cheap to run.
Check it gets up to temperature when you drive it. The old engine had a thermostat which was stuck open, so it took ages to warm up.