You want a war? thats like asking which is more popular NASCAR or NFL
football!

Kidding aside. heres my opinion. I use GSM and CDMA here so I have
first hand expirence with both.

GSM is a more popular Global cellular standard. it uses SIM chips,
this allows you to swap phones like you swap shoes. You remove your
chip from one phone and place it in another. GSM works both in the U.S
and the rest of the world. Unfortunatly in the U.S GSM does not have
much popularity in the hinterlands. I am unsure why that is but if you
are in the middle of Kansas, you need CDMA or Analog

CDMA is a closed proprietary standard designed by Qualcomm. This
standard does NOT use SIM cards in the U.S version and in the Asian
version they use R-UIM chips (they look and act like SIM chips.). Some
say CDMA calls sound better. I don't see that being always the case.
U.S and Asian CDMA phones are not compatible because of frequencies.
CDMA has some small pockets of popularity in Europe, however, again,
the frequencies make U.S and Asian phones useless. Qualcomm also
charges high per unit licensing fees to manufactuers and cellular
service providers. GSM, oth is an Open standard and does not charge
these fees.