I have but found it was too uncomfertable. The ring is about the size of th bottom of a coke can and about 5mm thick. I used it for 2 months and had no side effects apart from the fact that I could feel it, but I did have a slight prolapse after dd1 and that may have caused me to feel it more.

If you are really keen you could always try it and if it doesnt work for you take it out, much easier than removing implanon or waiting for a depot injection to wear off.