From what I understand the different carriers all use different bands and frequencies for LTE. ...
It seems to be localized by continent ... from Wikipedia 4G-LTE: "The LTE standard can be used with many different frequency bands. In North America, 700/800 and 1700/1900 MHz are used; 2500 MHz in South America; 800, 900, 1800, 2600 MHz in Europe; 1800 and 2600 MHz in Asia; and 1800 MHz in Australia."
Of course the Google page states :
Network
Unlocked GSM/UMTS/HSPA+ GSM/EDGE/GPRS (850, 900, 1800, 1900 MHz)
3G (850, 900, 1700, 1900, 2100 MHz)
HSPA+ 42
So there's hope that the 1700/1900 will be the ticket here. The service plan I'll be using when the back-ordered N4 arrives utilizes both AT&T and T-Mobile, so I'm eager to see if the LTE can actually work during the course of my travels, if indeed the phone is capable of it as the videos attest.