Whenever possible I use iChat or Skype to call people and I urge people to call me the same way.
There are a number of reasons for this but the number one reason is voice sounds quality. My fixed line phone sounds bad, my mobil phone sounds horribel. All mobile phones sounds horribel!
I paid hundres of Euros for an iPhone and pay hundres of Euros every year to my carrier. Why does it need to sound so bad?
My mother has a hearing loss and needs hearing aids. She can’t use mobile phones at all. Fixed line phones is possible for here to use, but no more than that. With iChat on her iMac there are zero problems, it’s like sitting in front of here.
Why? Because iChat has superior sounds quality compared to the phone systems. The same goes for Skype and I assume Yahoo, MSN, Google Talk etc.
The human ear can hear 20-20 000 Hz (when you get older you usually lose anything above 14 000 Hz) and is most sensitive around 2 000-5 000 Hz. If you got the bandwidth iChat and Skype has no problem handeling this.
The mobile phone systems apparently use ancient codecs (G.711 from 1972) that offers 300-3400Hz. No wonder it sounds bad.
Newer and better codecs of course exist but there seems to be a chicken and egg problem with the implementation. Handset manufactures sees no need to support it until the phone networks gets upgraded. The carriers sees no need to upgrade the networks until there are handsets that support it.
Lets hope they fix it until the next generation mobile telephone system. Until then I will do my best to make everyone use iChat and Skype as much as possible. Cheeper and better.