GNU/Linux has a far more intuitive interface on where to find your applications than windows which simply dumps everything in the start menu and/or under each developer's company's name
I would agree that Windows would greatly benefit from categoriztion and centralized package management.
For being an OS that likes to center on customization, however, sometimes Linux does seem to be a bit on the complex side.
Take moving around the icons on the bars/panes/whatever: In Windows, you can unlock the bar, move stuff around, and re-lock it. In Linux, the locking is per-item, and you need to go through the right click menu every time you want to move anything. It seems like a lot of effort to move icons.
In addition, Linux seems to have quite an aversion to placing anything on the desktop. It's difficult to move the trash and other items there.
but the opposite is true for windows where easy customization I can do in GNU/Linux I can't do in windows (ie, multiple desktops)
I would see that more as a feature rather than a customization. In addition, since it's another icon on Ubuntu's default desktop, it's more clutter - so you have to weigh the drawbacks of having another icon on the task pane over the benefits of multiple desktops.
In addition, a lot of the changes in Windows 7 seem to center around making things easier for the single desktop, reducing the need for multiple desktops. Grouped thumbnails and Aero Peek make it easier to switch between tasks with realtive ease. In addition, with widescreen and dual monitor setups becoming more common, the ability to put tasks side by side is becoming much less of a problem. And talking about side by side tasks, Windows 7 is even making it easy to put tasks side by side by allowing users to drag windows to the left/right, and the windows will fill the left/right half of the screen. A lot of new features - but without adding a lot of clutter.
The default configuration of Ubuntu is cluttered. Three text menu items at the top, the user name (which strangely enough appears even when set up for single use), not one but two bars, a "show desktop" icon, and the virtual desktop icon - in addition to the standard stuff that other OSes already have, like the date/time and networking icons.
The best features are those that work without adding more icons or text to the menus. Aero Peek didn't add any new icons - it just requires the mouse to hover over the icon representing the running application.
Ease of use is not about shoving as many features as you can on the lowest levels of the interface. It's about focusing on the current task, and working in a transparent manner without distracting the user with lots of icons, text, and messages. Two bars filled with stuff doesn't accomplish that.
I've experience enough with both computer literate and illiterate users and the only argument you will not hear is that they find Linux is harder to use than Windows. Some people that migrate miss a few features they have been used to, but that's it.
Have you asked them if they think it's simple? Have you asked them why they think it's more simple and/or complex? Could you be more specific as to you you mean by "harder to use?" How do you use your computer? What types of usage patterns do you see in other people as they use their computers?
Yeah. Microsoft did a remarkable job to promote OpenOffice, because the few Windows users we have in our company hated the MsOffice 2008 UI so much that they were suddenly remarkably happy use OpenOffice rather than MsOffice.
Businesses and people are often conservative by nature - they generally abhor change. Doesn't mean the interface of Office 2007 is any worse - just means it's different enough that the business didn't like the idea of spending a lot of time re-training its workers.