I personally prefer GSM because more people globally use it. GSM phones can be “unlocked” and you can pop out the SIM card and use a different one…from anywhere in the world! It’s really awesome to be able to do that when you travel. You can use an unlocked GSM phone with ANY carrier you want. You see people do this with the iPhone, some people unlock it and go to T-Mobile instead of ATT.
It’s also nice if your phone broke or you just want to switch phones for a day, so you can pop out the SIM and put it into a different phone.
I used to have Verizon and the CDMA network annoyed me. No SIM card, less freedom when traveling, wouldn’t work in the countries I visited, and I couldn’t switch phones when I wanted to and because it was CDMA, I couldn’t unlock it and switch to another carrier.
I know that CDMA is popular in the US (Verizon and Sprint) but else where in the world (Asia, Europe, etc), GSM is preferred. I will admit, in the US, CDMA has better coverage out in the country compared with GSM, but that’s no reason for me to switch.