They aren't the sexiest gun in the world but it should slow down the zombie hoard.
I think the Springfield Armory SA8 is the best out there as long as you get the one made in the Greek factory and not the junk aluminum receiver.The stamped S/A's are H&K spec just make in Greece on H&K machinery (G-3).
I would not consider any of them (ok maybe a vector).
The PTR's have issues with bolt gap (which is major).
I think you would be better served with an FAL variant.