As this image shows, it wasn't easy to port a complex Windows application to other operating systems:
... but the results are surprisingly good:
The Mac version has a polished UI and great features that aren't available in Safari: full-screen mode, bookmark sync, extensions and themes. Some Windows users would probably like to see the menu from Google Chrome for Mac.
Chrome's Linux version has improved a lot since the first dev channel release and will probably compete with Chromium, the open-source version of Google Chrome. For those who don't like the GTK+ theme, Chrome lets you enable the classic theme from Windows.
Chrome 5 has many small new features: extensions in incognito mode, reordering toolbar buttons, disabling individual plug-ins, native geolocation, new bookmark manager which is now a web page, zoom settings saved for each domain, Integrated Windows Authentication and more. It's also much faster than Chrome 4. An important missing feature is the built-in Flash plug-in, which will be added in a future update, when Adobe launches Flash 10.1.