Stevey started with getting booted and then came up with some cool stuff. NextOS. Realized that it's GUI/UI was not user friendly so put some cool-aid on it and then watched all these nay sayers and eye candy booers later boot it up because their previous version was worse than mac os 9.
osx core is free to download == darwin == BSD
GUI/UI are Steve o's property, however xcode is free to download and to make apps with. iphone with it's access to millions of people is $99 a year (well at least to signup)
Back to topic.
GUI - I would refer to as being the graphics a bling that users visual see. Basically the theme.
UI- are the elements that tie the GUI to the code. Thus the menus, location of buttons, usability features, the amount of user interaction and such. This is the area that programmers probably are the worse at. Not the graphics that so many will admit that they are horrible at.
So I would say that the "experience" that I'm referring to is actually the UI.
How many clicks do I have to go through to play my tunes.
Where are the settings located? Are they organized into 1 central area or are they per application? Or even worse a mix between the 2???
OSX UI is intuitive. Can I do it? yes. Can I find the location of the function easily? yes.
XP UI is anywhere from great to WTF? Can I do it? yes. Can I find the function? yes, after googling how and then still going through loops.
I truly hope that windows has fixed this with win7.
I mentioned this in another thread when we were talking about user interaction while driving. CF has a doable theme but from there on out when you use the UI for a while you start to get frustrated when you realize that menus jump around when you go between functions.