I haven't used Google Chrome much, but it's been interesting following Chrome/Chromium development on the blogs. The things that make it to the blogs are neither too vague so as to be uninteresting nor too detailed so as to seem unimportant or trivial.
The Chrome folks have a lot of cool ideas (especially about UI), and it's neat seeing fresh ideas in the web browser arena. One of my favorite little gems so far:
In most tab strips, when you close a tab the other tabs expand to fit the space that has just been made available. The upshot of this is that the close boxes of the remaining tabs all move around slightly, which makes it harder to quickly close tabs by clicking in the same spot. [...]
For Chrome, we came up with something a little different. Realizing that maintaining a fixed width for tabs when closing them would keep close buttons aligned under the mouse pointer, we designed a system whereby the tab strip will re-layout when you close a tab to fill the gap left, but not resize the remaining tabs, until you move your mouse away from the tab strip [...].
(Ben Goodger, "Tabbed Browsing in Google Chrome")
That is clever. An engineer did the right thing there.
In addition, it's interesting to be able to read about the software development methodology employed by Google, which one usually doesn't hear too much about. For example, the way they use usage data to identify newly coined words that should be added to the spellcheck dictionaries or the way they systematically regression-test the renderer on the million most popular web sites. Most free software projects don't have these resources, and most proprietary shops don't publicize these kinds of details.
Update, 30 Mar 2009: I tried some Chromium builds on GNU/Linux and they are blazing. Wow.