Pros of Google Chrome:
* Synchronized bookmarks. I know that firefox has this as an add-on, but I like knowing it won't break with an update, is stable, "just works", and also my bookmarks shows up in google docs.
* Better use of real estate. More of the page shows up because Chrome has eliminated the bottom status bar and file menu.
* Doesn't have this weird issue where a flash video will start lagging one second out of ever 10. This shows up after leaving Firefox open for awhile. This issue also affects typing; if I am typing a long message I'll discover parts are missing where Firefox momentarily froze. The fix is to just close and reload Firefox, but it's still annoying. Started in 3.5 but hasn't been fixed in the most recent Firefox yet.
* You can drag a tab outside the current window to open it in a separate window, and it keeps the same page open without reloading the page. Very nice if you are watching a video, and want to have it display separately on your second monitor without having to reload it. This also works in reverse; drag a window to a second instance, and it will seamlessly show up as a new tab on the other window without reloading. Supposedly Firefox will support this soon.
* Omnibar (combining the url and search bars into one). File this under the "why didn't anyone think of this before". Makes total sense.
Cons of Google Chrome:
* No dropdown list in the omnibar that you can click with your mouse without entering text. I was in the habit of using this to remember recent sites I had visited in Firefox without going to history. However, it didn't take long to get over this, and in fact it is not really a con anymore because I am now fine without it.
* No RSS feeds in bookmarks. This one I really miss. I like being able to go to an RSS folder in bookmarks and quickly seeing if anything new has been posted in my subscribed feeds. In Chrome the best you can do is subscribe to feeds in Google Reader, but I find this to be a hassle and often now forget to check my feeds for updates.
* Not as many add-ons. I miss the form text-saver add-on (in case you get logged out before you submit a form) and a fully functional greasemonkey. I don't mind not having something like adblock since I realize websites need me to see their ads in order to survive.
* No firebug. Google Chrome dev tools are pretty decent however and make a fair substitute.