Ultimately, it is not the case that you spend hours a day staring at, but rather what's on the screen. In this regard, the PowerMac shows one of its best sides. From the stark grey boot logo to the network preferences panel, OS X presents a beautiful environment throughout. It cannot be stressed enough that the beauty of the environment is a function of many factors, of which the Aqua theme is actually only a small part. The most noticeable thing is the use of color. While OS X sticks to a palette of blues and grays, it occasionally uses splashes of reds, purples, and yellows to liven things up. Keeping an exciting interface like Aqua usable on a day-to-day basis is a challenge, but Apple accomplishes it by doing an excellent job of laying out interface elements. Even with the big icons and colorful widgets, nothing ever feels cramped or cluttered. Nothing ever seems like it clashes or is otherwise out of place. The attention to detail in this regard is astounding. For example, almost nowhere in the interface is there a small icon. Small icons are generally quite ugly, since they are hard to make out as anything but formless blotches of color. The only place they appear is in some window title bars. Interestingly, Apple seems to have removed them in the newer Platinum theme.
The menus are just incredible. OS X has the best menus, bar none, of any OS I have ever used. Apple seems to realize how important menus are in traditional computer interfaces, in a way few others do. OS X's menus are big, uncluttered, and above all, clear and easy to read. They use big fonts, big arrows, big symbols denoting shortcut commands, and ample spacing between all the elements. Of course, OS X has the top menu bar which I love so dearly, and which, despite what some people think, works just fine on a large monitor. It also has the very-useful "application name" menu item, which contains the miscellaneous entries that always get scattered around randomly in other menu systems. Seriously, has the "exit" item ever made sense in the "File" menu? In all, OS X 's UI is a noticeable step up from GNOME's, and a giant leap up from Windows's. In comparison to GNOME, it is more colorful and artistic, but also a bit more busy. GNOME is more subdued and spartan, but lacks some of Aqua's excitement. In this regard, personal preference plays a big role, and I can see many people preferring GNOME's more laid-back style. Interestingly, I find GNOME quite a bit more rigorously consistent in look, but I find OS X's slight variances in appearance to be more pleasing in day-to-day use.
Expose is great. I haven't missed virtual desktops at all in OS X. My benchmark for window management is a long Matlab session. I've found that after a few hours of working in Matlab, I end up with a couple of dozen windows for simulation models, figures, graphs, m-files, etc. Windows absolutely chokes in this scenario, leaving me with a "Matlab" entry in the taskbar with a linear list of every open window. Of course, the list is full of completely non-descriptive names like "Figure 1". Expose brings order to this chaos, and even allows me to switch to a text editor window to type up some results without completely messing up my workflow. Expose is a wonderful example of taking advantage of the natural strengths of human users, in this case image recognition, to solve a complicated interface problem.
Since I stare at text all day, I am quite picky about the quality of text in the interface. After living with it for a week, I have to say my feelings on OS X's text are mixed. One one hand, I have to congratulate Apple for using nice, large fonts throughout the OS. Apple's default UI font is Lucida Grande at 13 pt, equivalent to a Windows font size of about 10 point. It is a pleasure to look at compared to Microsoft's microscopic 8 point Tahoma font. OS X's renderer seems to use very light hinting, so the rendered glyphs retain most of the aesthetic qualities of the original font. In comparison, Window's ClearType renderer contorts glyphs until they their original forms are unrecognizable. Now, on the other hand, OS X's fonts are quite fuzzy compared to ClearType's. Having first used anti-aliased fonts in BeOS, I have no problem with fuzzy fonts. My main requirement is that the rendering be sufficiently sharp to keep me from getting eye-strain at the end of the day, and OS X's renderer meets that criterion adequately. I must say, however, that FreeType with auto-hinting is still my favorite renderer. It is in between OS X's renderer and ClearType in both shape accuracy and sharpness, and to my eyes it is a happy medium.
One aspect of interfaces that often gets neglected is the tactile interfaces to the OS. Luckily, the tactile interface is something that Apple does not neglect. OS X's keyboarding interface is excellent. While OS X is often considered to be an OS for new users, it is obvious that its keyboard shortcut mechanism is designed with power users in mind. The shortcuts are consistent, easy to reach, and thorough. The mousing interface is comparably good. Menus are very easily navigable, with hysteresis delays tuned to maximize the feel of control. It is in areas like these where Apple's long background of hard UI research really shows through.
I do have a couple of gripes about the UI. First, file typing is a mess. It seems to me that an OS as otherwise elegant as OS X should use a more elegant method of file typing than file extensions. The situation would be better if OS X at least handled file extensions properly, but it doesn't. It seems to use a weird mix of extensions and creator codes that results in completely unpredictable behavior. For example, I originally wrote this article in TextEdit. When I opened it up in Safari, it would open it as a plain text file, not an HTML page. I tried copying the file to another name via the CLI, but that didn't work. However, when I opened up VIM in the terminal, and pasted in the text of the article from TextEdit, the resulting file opened up as HTML in Safari. At this point, I still have no idea what happened, I've just taken to editing HTML files with Emacs instead. I also find it difficult to determine when a file extension will automatically be provided and when I must type one. I really can't stand that Finder, by default, shows some file extensions, like .pdf, and hides others, like .png. In comparison, GNOME handles file typing wonderfully. I've never been surprised by what file type was assigned to a file, and the way the GTK+ file dialog is set up, it is absolutely clear what the actual file name will be when the document is saved. Also, it's nice how in GNOME naming a file with a particular extension will cause the application to save the file in the format associated with that extension. I tried to do this in OS X's screenshot utility, but instead of saving the file to the format I wanted, it simply yelled at me and said that the extension must be ".tif". My last gripe my seem minor, but it has been bothering me quite a bit. Safari's "Show in Finder" icon in the Downloads window looks exactly like the Spotlight icon. It is completely non-obvious that the icon has anything to do with the Finder without reading the mouse-over text. Actually, the "magnifying glass" element in general is overused in OS X, since it's part of the Sherlock and Preview icons as well.