MTP stands for Media Transfer Protocol and is a straightforward method of moving data between devices. It has been designed for Android OS, and rather than making the raw data on an Android device available to a computer, it instead provides the computer with a directory of the data available.
The computer then makes requests for files in order for them to be transferred. ADB (Android Debug Bridge) is a faster method of connecting, whereby the computer can send direct commands to an Android phone. That means that, rather than sending queries and waiting for access, it can quickly and directly change files on the device.