How Chromium and Chrome differ from each other

The logo of Chrome and Chromium only differ in the color - the logo of Chromium is blue while Chrome is green, red and blue, and they are all developed by Google with the same UI, which is hard to distinguish between each other.

Commercial and FOSS

The Chrome browser is commercial which means that the original code is not known by the others except the Chrome developer while the Chromium is FOSS(Free and Open-Source Software) which means that the original code is shown to anyone.

Chrome is usually better than Chromium in performances as it is commercial maintained by Google while all the upside of Chromium is absorbed in Chrome.

However, Chromium is maintained by the community and the code is open to anyone, so there would be less backdoor than Chrome.

Which should I choose?

There are two choice: convenience and privacy, if you prefer convenience, choose Chrome, and if you prefer the other, choose Chromium. But that don't mean that one of them is absolutely lost if the other is chosen, in fact they both work well in each side.