Implanon or Mirena/IUD

I'm headed in to get my Implanon removed. I asked for Depo and the place doesn't provide it... I've had mixed outcomes each time I've done Depo anyway. Implanon has been a ride. Sometimes light or no period. Sometimes (like now) my cycle lasts 3 or more weeks. I gained A LOT of weight this year. I have gained steadily on it with no change in my life. My type of job hasn't changed much, I walk more in this job than I ever have and I've never had a weight problem until the last couple years. Just not sure about Mirena either. 5 years seems like a long commitment. . Any suggestions, side effects, horror or love stories welcomed!