I have a Bryan Artificial disc in my cervical spine and it is just wonderful. The disc itself is like a very small rollerblade wheel that sits between to metal shells. It has a central spindle that allows for movement. I ruptured the two discs beneath it 19 years ago and the two levels were fused which put pressure on the remaining discs and was no doubt a factor in the level above rupturing.
It has made a big difference to my life. The surgery was horrible with a major retraction of my throat and I couldn't swallow for a long time after without food going up instead of down and it ached terribly. But it is so much better now than it was. For me to have fused another level would have been wrong but at the same time I couldn't function through the pain of the 3/4 disc having ruptured. I can hear the artificial disc creak when I move but it is wonderful technology. If you are giving the option to have one instead of a fusion
the benefit outweighs the discomfort of the surgery. It maintains natural movement and function. That is my opinion and I have had mine for 9 years now.