I agree that Bilateral CI's are probably not going to be that common but are getting more and more common. I know quite a few users who have bilateral CI's. Most users have had little to no hearing before and are just happy to have the ability to hear sounds again. They may be able to understand speech some but better than nothing. When considering what they can hear along with reading lips, they can likely do well. For me, I had good hearing before loosing mine. Quite possibly Bilateral CI's may be more popular for those who could hear prior to loosing their hearing. Just a guess.
For me, I've been bilateral for almost 8 months with my first CI almost 2 years and 8 months on the clock. I initially pursued a second CI to help with sound localization and understanding speech along with surrounding noises. I was nervous at having only one CI in that if I had a problem, I would be without sound. I have now realized there is so much more. Fullness, Ease of Listening, Less energy devoted to hear and understand which gives me more energy to do my job and things I enjoy without being exhausted at the end of the day. I'm sure many of you can relate.
I know I have benefited quite a bit from my second CI in that I have been able to turn down the volume of my first CI a couple times now. I'm not having to run my first CI to the ragged edge like I was prior to getting my second. It is not that I was always messing with the programming to get it right. I was missing some speech but not a lot. I scored 100% on speech recognition with my first CI after 4 months post activation. I was tested at 5 months with my second and scored 97%. My second CI activation is going a little slower but progressing very well. Not bad in a controlled environment. For me, the real test is out in the real world and only I knew what I was able to hear and what I wasn't. With two, I'm very satisfied that my ability to hear and understand is better than when I was deaf in one ear and had good hearing in the other. My sound localization is getting quite good.
I have some suggestions that I have identified during my last mapping session that I will share with my Audi. I want to know if the mapping program can be modified and tweeked a little which could help even more with sound localization at medium volume levels. Every time I get a new MAP, I learn another aspect of the program that makes me want to play a little more and try more new stuff. I'm not sure my Audi likes spending 2-3 hours getting both right but every time I go, she learns something new so she can help her other patients.
This past weekend, I took my race car to the track, first time in a while. I only wear one CI in my helmet because getting them both tucked under is a little difficult. What I noticed more is when I took my helmet off and had conversations with fellow drivers using only one CI, I had a hard time understanding and the background noise was difficult to deal with. How quickly have I adjusted to two CI's. When I had both CI's on, I noticed the background noise but could carry on a conversation without much difficulty. At least no more than someone with "normal" hearing or at least un-aided. So for me, this is another reason two are better than one.
For me, having Bilateral CI's, there are so many more benefits than just "sound localization". How to put these experiences and feelings into words is more difficult that anyone can probably imagine. It is like the question "What does LOVE feel like?" To each of us, it may be similar but may not be the same. I can try to put it into words but someone may disagree. I know what it feels like to me. To someone else, it may be different. I think Bilateral CI's may be similar. Some may benefit from it, some may say it hasn't helped much. What they feel and hear may be different that what it is like for me.