Not personally, but a forum specific to CI users may be helpful. I found one, but there are probably others. http://www.hearingjourney.com
It sounds like your wife has made her decision, and I assume it wasn’t arrived at lightly. As strange as it sounds, I think she is at an advantage because she already has experience being deaf, so in a certain sense, she hasn’t much to lose (although many deaf people would argue otherwise). At any rate, I wish you both the best with the procedure – and the care, recovery, adjustment, and wonderment that follows.
As has been pointed out, a cochlear implant doesn’t restore hearing in the traditional sense. A quick web search on how they work will explain how only a fraction of nerves are used to detect sound as compared to the ear. As a result, a person has to learn how to identify these nerve impulses as not only sounds but words. One way I read about how this was done is that a person pronounces words and sentences while hiding their mouth to discourage lip reading. The person with the implant is able to read what the person is saying (like a flash card or something), so they learn to associate the sound they are hearing with the words that are being spoken.
I know one person with a cochlear implant (my boyfriend’s mother) and she has had it for a few years. Unfortunately, she also has other neurological issues and (perhaps as a result) has not been able to “train” her new method of hearing. All the time, she says “I hear, but I don’t understand.” Truly, it breaks my heart because she is so isolated. We have tried putting her and her husband in touch with a local, community-based deaf center for help with either training with the implant or learning some basic sign language – we even drove her to meet a coordinator – but they won’t take any help. My boyfriend and I have learned some ASL and have tried to teach them some simple letters and signs they could use to communicate to each other, but they don’t want to. Year after year, when we visit, we have to resort to writing on paper or (because its faster) using the notepad utility on the computer. At any rate, her situation is different than your wife’s, because she had fine hearing until later in life. I don’t believe she’s yet accepted what has happened.