Considering our FE had no power windows to get stuck up, no stock radio to go haywire, and no alarm/keyless entry that could go bonkers... it's about as reliable a modern car as you can get...
It's not any more fragile than other compact cars of the time. The aircon compressor is relatively more expensive compared to other cars, but chances of breaking it with proper maintenance are low.
The only big issue with the FE is keeping the carbs clean and in tiptop shape. Dirty carbs equal poor mileage. With proper oil changes, filter changes and carb cleaning every other oil change, fuel economy is pretty decent.