Implanon.

Uh..So..ive had this thing going on five months now. No period the second month. uncontrollible bleeding the third month, no period last month..and this month i spot everytime we have sex. WTF.. anyone else have issues with this damn thing.. im seriously concidering yanking this thing out my arm once we get settled from our move.

So, upside of implanon - I didn't get pregnant while I was on it.
Downside - my periods were irregular as hell, and are still shady at best over 2 years later  

I'm thinking about getting one, my OBGYN said it's common for cycles to be unregular for the first 6 months or so.

It can take a while for your body to regulate while your on it. It's different for everyone though.

I had implanon after my son was born and kept it in for about 8 months, then got it taken out. I had 5-6 week long periods, massive migraines, I gained 25 lbs....all round I hated it and will never regret getting it taken out.

I got mine in October 12th of last year, I just now finally stopped bleeding/spotting. Up until about 2 weeks ago I bled/spotted everyday. I still bleed most the time DH and I have sex but it's becoming less and less. It's kind of annoying but I have no other choice since I don't have insurance and we don't want another baby yet.
Oh and i gained like 30 pounds after it got put in.  
Other then those two things I'm starting to like it.