@the_final_countdown I don't know for sure, but I would imagine any death that takes a while is at least unpleasant. If you want completely painless, you are going to have to jump, shoot, or find pure F. Two of the three of those are much more violent options than SN, but they are instant.
Edit: I think the exception is an exit bag, done correctly. That you just pass out and if it works, don't wake up. But there is a good chance of permanent brain damage if you do survive.