Chrome is a modified Chromium, basically a build of Chromium customized by Google to their own specifications. For the most part they are the same, and whether the differences matter to the user will vary.
Chrome includes crash reporting built in as well as recorded user metrics (ie. tracking) that are sent to Google. They *can* be disabled but are on by default, as is auto-update, which Chromium does not. The sandbox is also always on in Chrome. Chrome also includes proprietary code modules to support flash, H.264, AAC, MP3 support in HTML5 without the use of plug-ins. It is generally available only as deb or rpm packages and is reportedly a touch slower than Chromium, especially on downloads.
Last edited by NyteOwl; 11-14-2012 at 02:19 AM.
Reason: Fixed typos