I've posted a few times in response to women in this forum considering implants... don't do it. Once it's in there, you're stuck with it regardless of the side effects until your doctor and yourself eventually give up and cut it out.
For me, it worked well for 8-9 months, and then the hormone level dropped just enough that I was stuck in a constant state of menstruation. They tried oral hormones multiple times to get my body back on a cycle, which kind of defeated the whole purpose of getting the implant to avoid having to remember to take pills. I spent *months* bleeding before finally having it removed.
My gynecologist informed me that she is no longer recommending implants to any of her patients, because every single one has had to have it removed before reaching 3 years. It's just impossible to control it once it's in there and something goes wrong.
I moved from the implant to the NuvaRing. It's been great - you leave it in for 3-4 weeks and then take it out for 1 week. I haven't had any issues with it. I use a calendar on my computer and phone to mark all my "ring in" and "ring out" days ahead of time, and they pop up with notifications when it's time. It's like having an implant, only you have control over it.
I hope this helped, or was at least informative :)