I had one in, and it was inserted by a nurse, not a doctor. I had no problems with the insertion.
But after having it inserted i bled for 6 weeks at a time, and had 2 weeks of no bleeding inbetween ever 6 week bleeding period. It was extremely light, but was still there and annoyed me.
I was also diagnosed with agoraphobia and mild depression not too much longer after having it put in. I must admit though i was in a relationship i did not want to be in, which could have caused the depression, but i didnt want to be in the relationship for a year prior to having the implanon put in, and i managed fine before then. I was a mess.
When i had it taken out in feb this year i was a better person to say the least, i was able to come off my medication for depression and agoraphobia, and my life just seemed so, fantastic

I would NEVER use the implanon, ever. It messed with my body so much, and i couldnt do that to myself again!