difference between these cases and the Ncase M1 is that the Ncase more or less gave up ATX PSU in favor of SFX. sure the Ncase officially supports ATX PSUs, but it's 'not recommended', and will gimp the cooling capabilities of the case.
honestly, for small form factor, I agree with the creators of the Ncase, when you're building a compact machine, why bother using a PSU that's practically the same size of your mobo and takes up over 1/3 of your case volume? the SFX PSUs from Silverstone will power everything you need