While faster than Firefox, Chrome 4 isn't a great deal faster than Chrome 3.x. On the same machine, my older copy of Chrome came in with a time of 553.0 milliseconds. I was unable to test this production version of Chrome on Linux or a Mac because those versions are still in beta.
But speed isn't the real news in this latest version of Chrome — it's the new features that demand your attention.
While not the equal of Firefox's rich eco-system of add-on programs and extensions, Google extensions already amount to a versatile collection of software. Some particular favorites of mine are AutoPatchWork, which automatically loads the next page when you reach the bottom of a multi-page Web story; IE Tab, for those pesky Internet Explorer-only pages; and Docs PDF/PowerPoint Viewer, which displays PDF and PowerPoint files in the browser without needing to load Adobe Reader, PowerPoint, or PowerPoint Viewer.
There is also a useful selection of extensions that expand the utility of Google's own software. Extensions of this sort that I've found useful include Google Mail Checker and Google Calendar Checker.
Some of these extensions are a bit rough still around the edges. I would really like to see the Calendar Checker work with more than just the one default Google Calendar. Still, considering that Chrome extensions have only been around for a few months, I'm impressed.
Chrome also now has built-in browser Bookmark sync. If you're like me and use several computers, bookmark syncing is the best thing since sliced bread. In the past, I've used Xmarks, which works across Web browsers, but if I were only using Chrome, I'd seriously consider just using its built-in bookmark sync feature. If you still want to stick with Xmarks, it's still supported in Chrome.
On top of that, Chrome now has WebSockets support. This new API will eventually make it possible to maintain a persistent bi-directional communication connection with server-side processes. Last but not least, Chrome also supports its own new notification API. This will enable Web designers to push data, such as event reminders or status updates, via a panel in the user's status-bar area, to users.
If you add all these 'invisible' changes together, you can see Google is continuing to work on making the Web interface do double-duty as a persistent desktop interface, ala its forthcoming Chrome operating system. Once the IT infrastructure is in place and the bugs worked out, you'll be able to use Chrome for much of your work whether you're online or not.
For now, though, what's important about Chrome is that it's an outstanding Windows Web browser. Based on what I'm seeing, we'll have Chrome 4 soon on Linux, but Mac users may have to wait for early spring before they can use it. In the meantime, Chrome 4 has already become my Web browser of choice on Windows.