I believe that the user interface that an application is the key of success. I've seen excellent programs from the aspect of code, but with terrible GUI. That's why Winamp for example is very popular and some other programs are less popular.
They secret of Fruity Loops is their simple and handsome GUI.
I believe Didier's words say it all:
"
Sonikmatter: What's your view on Cubase, Logic and Sonar?
Didier: They are classics. You know, like books, that you wished you had read, but don't want to read. They're the ones that are supposed be used, but are too scary because of their complexity, and you don't really 'want' to learn them. So if you don't actually have to learn them, it's hard to start, and I never dared to. That's my opinion for Sonar and Cubase, as I don't know Logic, which seems to have a worse learning curve. They're probably the best tools for what they're supposed to do, but they're certainly not applications you can use for fun or have fun whilst using."
