Google have updated Chrome dev (15.0.849.0 dev-m) to re-enable one of the dev features that was taken out which is the Profile switcher located at the top left of the window.
It was briefly enabled for a few days with an image of a cupcake and I jumped on it immediately. I tried doing it with Firefox last year but it didn't work very well as you could only have one window open for the secondary profiles which wasn't very convinient.
Google have got around this problem and the profiles switch as expected. Unfortunately the new profile windows don't pick up the updated themes which I added to easily distinguish the different profiles, the only separation now is the colour of the profile icon. Although the theme does work when changing the target path of the icon to:
"C:\Documents and Settings\jtombs\Local Settings\Application Data\Google\Chrome\Application\chrome.exe" --enable-extension-timeline-api --user-data-dir="C:\Documents and Settings\jtombs\Local Settings\Application Data\Google\Chrome\User Data\profile_1"
The problem with this is the profile changer icon disappears. But as with all development software you have to work through all the bugs.
The benefit of profiles is to carry on using Chrome but be logged in to the same site using different logins which is great when testing a site with different user permissions. You can also have different bookmarks and the history is contained in each individual profile.
So I have a personal with my personal email accounts and Twitter but have a couple of development profiles which I have logged in to my works sites with different users with different permissions rather than having to log in and out or use different browsers (i.e. Firefox, Opera and IE).