Every car has it's own problem, every engine in Mito has its problems, bigger or smaller.
100% true, and with second hand cars you never know what skeletons are in the closet.
That said, i'd say the 1.4 16v or 8v are about as bomb proof as it gets in an alfa. Engine wise the only foible ive found on my 16v is that the original thermostat housing is apparently plastic from the factory, which gets brittle and cracks. Luckily my garage caught it and replace it with a metal housing before i was left stranded.
Engine wise, the 16v is about as simple as any modern engine gets, parts are cheap and work is again, as simple as it gets on a modern engine. Ive swapped a clutch, swapped the timing belt etc.. There is also plenty of space to work, since the engine bay is large enough for all sorts of turbo gubbins, which are missing on this engine. If it werent for the peeling clearcoat making my mito pretty much scrap value, i suspect it would happily hit 300k kms on the engine side.
That said, its not fast, and while its been a perfect daily runabout, and i love the 6-speed, if i were to buy a mito again with a bit of fun in mind, i'd get any 1.4 turbo version, and just budget for potential problems (and inspect/fix them immediately)