AT&T LTE vs Verizon LTE

My contract with AT&T is done. It was a mostly positive experience. I am out side of Buffalo, NY and both Verizon and AT&T have LTE in the area, but not in my town. LTE is supposed to be available in my town before the end of the year. I have heard from a lot of people that GSM/LTE and all advantages with GSM is better than CDMA/LTE but they really can't tell me why. Is GSM really better with LTE than CDMA? Is there anyone who can either share info AT&T's LTE vs. Verizon's LTE from a tech standpoint and the advantages and disadvantages of each carriers technology.