To create a web browser you need some kind of rendering engine. And writing rendering engine that correctly handles current HTML, JavaScript, CSS specifications is hard. On top of that you build features like bookmarks, password manager, etc. I do not have a problem with some browser using Chrome rendering engine, if they remove all the sketchy parts, like sending every url that you browse to some central database, or backing up your passwords on Google server.

So, in the end, being based on Chrome rendering engine is not a damning quality in itself.