The one the phone comes with from the carrier is usually the best one for their towers.
LTE is 4G. UMTS is 3G. GSM is 2G. CDMA is a totally different technology, used by Sprint and Verizon in the US, and some carriers elsewhere in the world. It can refer to 1x, which is like 2G or CDMA 2000, which is like 3G.