I just got a cochlear implant in the first week of October. After doing some research, I opted to get the Med-El brand. A neat feature of the Med-El is a one piece external component option called the Rondo. I really like this as it keeps your ear completely free and disappears completely under long hair.
As for the quality of sound, it is different for everyone. I was told it is affected by everything from the condition of your cochlea and remaining residual hearing (if any) to the exact position of insertion of the electrodes, and also how much your brain remembers how to process speech. There are some people who never get speech clarity with a cochlear, but they gain sound awareness.
For me, I had lost my hearing in January 2015 due to an auto-immune attack that resulted in sudden hearing loss. Since, I had not been "deaf" for very long, the prognosis was positive and meant less rehabilitation therapy than someone who had been deaf for a long time or for their entire life. One of my ears can and does use a hearing aid, but I was asked not to use it all the time in order for my brain to better acclimate to the cochlear.
Two weeks after my surgery, my device was activated. I was able to hear voices and interpret speech immediately, but I admit that it was most unpleasant. All voices sounded like robots and although I could tell that there were different voices, they all still sounded extremely robotic and I could not distinguish male and female voices. When multiple people spoke at one, it sounded like a bunch of robots arguing inside an echoey metal dumpster. I was disappointed, but was told many adjustments need to be made and it can literally take a year or longer for your brain to completely adjust to the cochlear. When I wore the hearing aid as well, I was able to gain far more speech clarity and word comprehension and things sounded normal.
After a month passed, I went back for a scheduled visit, I mentioned that I did not like the robotic voices. She made a few adjustments and suddenly voices sounded much more human! She said that it will get better as time goes on and more adjustments are made so this is definitely a positive thing.
The bottom line is that the experience with a cochlear will be different for everyone. In my case, I had no useful hearing in my left ear and the right ear alone was only getting about 45% speech discrimination. Living life this way is very difficult. I made the choice to get the cochlear to improve the quality of my life and although I've only had it a short time, it already has! I would make the same decision again if given the choice. I think that it is a personal decision that everyone has to make for themselves. I wanted to optimize my ability to hear and I know that this has helped me a great deal. I am not saying "WHAT????" or asking embarrassing questions all the time because I didn't understand what someone was saying.
If you have questions about the experience, please ask. I have to believe that this sudden hearing loss happened to me for some reason. Perhaps it was to be able to help others and I will be happy to do so.
Right ear/ Left ear - no hearing
250 - 90
500 - 95
1000 - 95
1500 - 85
2000 - 80
3000 - 70
4000 - 65
5000 - 85
8000 - 85