I wouldnt put it that way. The Z gens are very well made and are smoother than the older gen and are robust as well if taken proper care of. The block itself may not be able to take as much abuse as the iron ones but that said, it wouldnt be too far behind the iron blocks and wouldnt give you any issues if you take care of it properly. The 2nz in my Charade is around 300k km driven and Alhamdulillah, it doesnt have any issues at all. No noises out of the ordinary, compression is fine and still packs a punch while giving me quite good mileage Alhamdulillah. Throughout its life, it has been run on liqui moly and a couple of times Ceratec has also been used.
About the 5AFE EFI-S, like @SER_GTR said, its a rare engine and its best not to go for it even if you find one as parts will be an issue later down the road.