Hanging is a lot more accessible than SN, as the latter requires more than just acquiring SN; antiemetic is not over the counter in some places which can be tricky for those without insurance. However, SN seems a bit more manageable considering that some people have difficulty finding the correct position for their noose which makes SI kick in.
I don't know if SN has lasting effects if one fails, but if you are found before total body death while hanging, you will have lasting brain damage, or even rendering yourself a vegetable.