It's basically Chrome, except they've removed the privacy issues because the normal Google Chrome sends lots of information back to them. It's small bits and data here and there but to me, this version of Chromium is a lot faster.
You could look at the changes made here or just go here and see for yourself.
The site itself is in German, but the link above was translated with Google. Good thing the browser is in English though.
The only downside about this browser is there's no auto-update feature. But I guess that's what you get when you want security.
Edit: You can actually still log into your Google email/profile and have all your other details from other Chrome browsers (extensions/themes/bookmarks/etc) synced to this browser as well. It's definitely one of the best browsers around and it's definitely stable.