All 3 implants are MAN-made devices, and any and all man-made devices can and will fail at some point. There's no denying that.
I just got my AB implant turned on yesterday and so far so good. No, I'm not hearing things, it's just beeping/busy signal tone on a phone line sort of sound going on right now, and feeling sensations in my head/ear with different sounds. But, as long as I keep feeding sounds to my left ear with the implant on, hopefully over time it'll get better and start sounding more like the actual sounds instead of beeping.