Apple has released a beta of Safari 3 for Windows. I will mostly talk about the UI compared to Safri on OS X and other Windows apps, but I'll also point out a couple new Safri 3 features.
It requires XP or Vista, so I won't be using it at home, where I'm frozen on W2K. :-)
It doesn't have a Windows-style title bar--it uses the 'unified' look of iTunes. Also, the top left and right corners are slightly rounded. Clicking in the top-right corner of the screen when maximized does not close the window. There is not a clickable control in the top left corner. I would have preferred a standard Windows window--among other things, the menu items just seem to 'float' in a big sea of grey.
HTML form textareas can be resized. (Sweet!!!) Form elements have a somewhat OS X-y look. Radio buttons and checkboxes look like their OS X counterparts. Dropdown menus are rounded and shiny but are not quite Aqua-y. I can't compare to Safari 3 on OS X yet--the installer requires a reboot. :-(
The installer includes a Bonjour component for Windows.
Text controls work as they do on a Mac. For example, if you're in a text box, the 'up' arrow brings you to the beginning of the line and 'down' brings you to the end.
It rounds the edges of a text box and gives you an 'x' icon (for 'clear') if you specify input type="search", same as you'd get in Safri on Windows.
Tabs can be dragged around, just like Firefox (stock? or requires an extension?) or Safari with Saft, which I love for that reason and many others. (Hopefully, they can keep making Saft for 10.5.)
Preferences are under the Edit menu. The Preferenecs window has rounded top corners, 1-pixel grey rules on the top and bottom and 2-pixel rules on the sides. So do other windows, like the 'Private browsing' warning. Those windows have 100% Aqua controls internally.
Don't use it for production work--I lost the first draft of this post to a crash. :-)
It has the menu option to spellcheck text areas but it doesn't seem to work.
The 'report a bug' icon is shown by default.
It has one feature that Safari for OS X will never have: a 'maximize' button. It also throws away other features--windows can only be resized by dragging the bottom-right corner. Grabbing the status bar (also off by default, grr) won't move the window.