Received my 6p on 1/20, fresh out of the box installed the 6.0.1 update and the January security patch. First day of use on AT&T, LTE was inconsistent and mostly stayed on 3G. After researching and reading through several threads I tried some of the solutions offered. My phone defaulted to Att nextgenphone apn settings during setup. Two changes worked for me, one was to remove the fota setting in apn types under the nextgenphone apn setting. The second was to use the att phone apn option. I've been using the att phone apn setting for several days now and have locked on to LTE consistently using that setting.