Here this might answer all your questions:
http://www.ringsofdesire.com/etching.html
I have a midsized etching on my back, not because of my job (in wearing my suit, no one can see it anyway), but because I've always been more partial to branding and scarification, but unfortunately traditional methods of scarring don't allow for truly fine detail and usually end up looking like something created by a 5 year old. Etching on the other does a much better job of permitting fine detail artwork in a scar. And in response to those who say that the result will not be long lasting - to a certain extent this is true, all scars fade, however there are certain things that can be done to ensure that the scar does not fade too rapidly, and to achieve a form of semi-permanence. I've had mine for over two years now and it's still a very well defined white scar. If and when it does fade, I'll simply have the pattern retraced and go through the steps of picking the scabs and rubbing with Isopropyl alcohol.
Lastly, I have a friend who has both traditional tattoos and etchings, her take on the difference in pain is the etching creates a greater sense of "burning" due to the lack of lubrication from the ink. I wouldn't know as I am clean of true tattoos, but I didn't find it so bad, more like being scratched with a sharp nail.
Good luck.