Some people think underfolders are extremely uncomfortable, but I used when when I was playing airsoft back in the day and I didnt have an issue with it. I think side folding mechanisms are more sturdy than underfolding too. If I had to choose, Id choose side folding.
Yeah there is a "real sword" brand Type 56-1 and it's sweet! Although try one with a full power 7.62x39, and you might find those metal cheek rests uncomfortable.