I can never get used to the latency when using a mobile, and so tend to use a landline whenever possible. I vaguely remember a work training course, where it was explained that the latency went largely unnoticed by some, but annoyed others. I think it depended more on cultural background than anything else, cultures that habitually leave a long pause in conversation will fare better than those that habitually engage “rapid response” in conversation.
To get an idea of the latency, and just how real it is, try the following experiment...
1. Pick up your mobile, and call your own landline number, and answer the incoming call.
2. Now put your *mobile to your ear and, speaking into the landline phone, count briskly from one to ten.
Chances are that the number you hear will up to be one digit behind the number you speak. If the effect does not bother you then congratulations, your brain can adapt to the latency. It bothers me intensely, however, to the point I find it hard to keep counting.
*oddly enough when I just tried experiment that and it only worked as described. With landline to my ear, speaking into the iPhone, I heard nothing at all. I guess the feedback and echo cancellation algorithms have got too good. Maybe the experiment might not work at all with more modern phones?