CDMA and GSM (now WCDMA) are almost the same. One is not inherently better than the other. What does matter is the network implimentation. AT&T is having problems because of their ability to handle the data that the users want, the size of their 3g roll out, and the hand off between GSM and WCDMA. The dual chipset would be expensive to implement in all of the iPhones, especially in countries where CDMA doesn't exist. Apple just doesn't make one item different for just one country. They are about the smallest number of skus possible.