4G is a Private frequency! That means that there is less interfearance from other devices. Because 3G is an open frequency, there tends to be a lot of other devices that run on the same band. Items such as:
- Cell Phones
- Baby Monitors
4G is a much more powerful signal, able to burrow through trees that are more then 300 meters from the unit on your home or business, whereas the 3G signal is dropped when it hits any obsticle.
The 4G technology allows administrators to balance traffic on the towers and even deal with one specific user that might be abusing the system. The older 3G systems have no way of intelligently dealing with increased traffic. In most cases the traffic forces the administrators to slow everyone down to decrease the load.