This article leaves out a major issue if you're an iPhone user (no idea about Android phones): LTE frequencies have not been standardized. As usual, it's the US that is the outlier, and the rest of the world have agreed on a standard.
For example, US iPhone models use GSM at 700b MHz, but won't work with European LTE (and vice versa) which use GSM at 850/1800/2100 MHz.
(And then there's my country, Norway, where we have only two networks which for some reason have decided on 1800/2600 MHz, which will work with none of the existing models.)
"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."
It doesn't seem like anyone's particularly standardized on frequencies.
Different parts of the world have allocated spectrum that's in use for other purposes, so the operators have to deploy LTE in the parts of spectrum that are available and they have a license for.
All these(700/800, 1700/1900, 2500, 2600) are standarized bands as of today, though different bands have been standarized at different points in time.
This will be less of an issue as time goes on, newer phone models will support the various frequency bands.
As a rule of thumb anything that's not standardized on iPhone is even less standardized on Android afaik there will be Android phones on all the bands that netwroks offer.
We're releasing an iOS app soon - hopefully within two weeks - and will be interesting to see how the LTE experience varies on exactly the same device across networks and countries.
Here is Apple's list of models and their compatibility: http://www.apple.com/iphone/LTE/
For example, US iPhone models use GSM at 700b MHz, but won't work with European LTE (and vice versa) which use GSM at 850/1800/2100 MHz.
(And then there's my country, Norway, where we have only two networks which for some reason have decided on 1800/2600 MHz, which will work with none of the existing models.)