'permanent' birth control

What do you consider as a 'permenant' method of contraception? 
Seen so many posts of girls saying they are thinking about having the shot or implant over an iud ... Why? 
If you go for a non hormonal iud you can get pregnant as soon as it is removed...
If you get the shot or implant it can take months for your cycle to return... (Speaking from experience) 
To me a permenant method of birth control would be sterilisation in either men or women?
Thoughts?