I get the impression it obviously isn't in the public psyche like hanging and jumping are. I suppose it must be relatively new.
As for peacefulness, reports seem to vary widely. I don't think it's completely painless. I get the impression though that for a lot of people, it's more in the realms of distress and discomfort rather than agony. But- feeling nauseous and being sick (despite taking antiemetics,) a racing heartbeat, laboured breathing, headaches are common side effects. I don't think it's just a case that you take it and gently drift off to sleep but yeah- reports seem to vary. I think it's best to read all you can here and make your own decisions.