All these reviews have me confused

Thania
So I just got the implant today! And I read millions of reviews before I considered getting it and I talked to the doctor who put it in, but right now in looking at more reviews on the internet who have got it or have it, and a lot of people say it's the MOST effective BC not some say they have gotten pregnant while on it, so I'm confused! Can you or can you not? And how likely is it?