The approach to user interface is completely up to the manufacturer and is completely different from keyboard to keyboard. Some provide a very intuitive interface and some don't. Some products require many "manual" hours and button presses to change a parameter while others are simply intuitive and require little research.

Not that it is all that simple. Some interfaces work for some but not for others and is a matter of personal taste. ( but there are always some interfaces that suck for everyone lol ).