N is considered the most peaceful of all existing methods. It is used in euthanasia.
You lose your consciousness very fast, no pain, no discomfort. Feels like you just fall asleep.
Cons: price, availability, long recovery if failed (though unlikely), illegal to sell
SN is peaceful as well but you will experience some discomfort.
A greater chance to throw up.
Takes a bit more time to lose consciousness.
Very easy to obtain, affordable, legal, fast recovery if failed.
Good method if you are afraid to fail.
N is my primary, SN secondary.
If you have money, are not afraid of customs/police, you can obtain N (there are only 2 sources available)
If you want an easier way out, then it is SN.
Both are peaceful, but N is more.