I live in the bastion of wilderness better known as the South Loop in Chicago, so I understand urban cell-tower issues. Physics would dictate that your LTE signal, at 700MHz, is going to be better than your CDMA signal at 1900MHz. Not to mention, the difference in speed means that it spends more time sleeping instead of at full power (more physics?). Try turning LTE off for a day. Your battery life will be much worse. That's why Apple could squeeze in a bigger screen, a faster CPU and more RAM with the same battery and get more hours of web browsing. Physics.