I thought I'd add to this forum as I found it very useful when trying to decide what to do with my implant, so my experience may help others. I had the implant for a total of five years.
I decided to go for Implanon due to its convenience (I frequently travel long distance with work so for example taking a pill at the same time each day was not going to be easy, and I was terrified by the thought of having a child). As soon as I had it implanted I started to gain weight and got increased acne. Sex drive reduced and I was more irritable and I felt less energy to do things. Despite this I was so terrified of motherhood that I continued with the implant.
I am 6 foot tall (180cm), so when I had the implant I weighed a steady (3 years) 72kg which was below the weight limit for the implant to be successful. With the weight gain I went up to 78kg which is above the limit. I started running to keep the weight down, and so ran half an hour 5 times a week which kept the weight from creeping up at 75kg (the weight limit!). Despite this, at 2.5 years I decided to get it replaced as I didn't want to risk the hormones running out (whether that was possible I don't know but as I said, I was terrified of pregnancy so erred on the side of caution).
I had Implanon replaced with Nexplanon, and the symptoms and side effects continued. With both I had no periods for the first 6 months, then almost constant trickle there after. I had bad acne and at this point had scarring. With work stress I couldn't exercise so much so my weight went up to 80kg, and I was generally miserable. Sex drive low, acne, weight gain, mood swings.
Then when I turned 30, after 5 years on the implant, I was no longer terrified about pregnancy. Knowing that I could deal with it if it happened, and that I would even be excited (although a little scared) by the prospect. I decided to have the implant removed. My husband of 7 years and I have decided to use the non hormonal contraception - tracking charts, condoms etc.
I was then worried about infertility, which I had read about, however I decided not to worry about this as there was nothing I could do about it. Work was very busy and this also helped keep my mind off it.
After two weeks of having it removed I had significantly reduced acne - few new eruptions, just scars remaining. My weight stayed the same. My energy increased and my husband says I became a nicer person (fewer mood swings).
In the 3/4th week I started to feel an extremely strong sex drive and extremely sore breasts and then around two weeks later I got my period. I've since had a second period (again around a five week cycle, however I expect it will settle in its own time).
My weight has remained... I heard that the body doesn't shift it on it's own, but needs to be dropped through diet and exercise (sigh!) but I find I'm not so ravenous now, and have picked up on my running and started some HIIT so hopefully soon I will be back to my pre-implant weight.
Anyway, I thought I'd share this as when I was looking for help I couldn't find many who'd kept this in long term like I had. Especially how long it took for periods to return to normal. I hope it is helpful to others :)