If you want a highly customizable browser, Firefox is it. Chrome is in its infancy when it comes to customization and they often make decisions that prevent power users from taking advantage of their browsing experience.
For example, they've disabled custom stylesheets in recent releases despite a clear indication that people were sharing themes, they have very old bugs that don't get resolved (like the stupid white flashes on dark themes), major accessibility issues.
Generally they try to appeal and prioritize regular users (which is fine) but go out of their way to make decisions that ignore power users and not even provide alternatives intentionally.
Finally and the most frustrating part is they don't value feedback. https://code.google.com/p/chromium/ is a joke and a waste of time. The most starred issues are often closed to the public when it reaches a certain level and users are asked to submit a new bug again if the old one is not fixed. This means that if there is still a bug, you have to wait months before other users experience it, find the time to search for the bug and star it, reach enough stars to get attention and then get a response. Bugs are often miscategorized and the wrong team has it in its backlog. It's a mess.
There isn't a feature in Chromium or Google Chrome that Firefox doesn't deliver.
Take it from a serious chrome user and extension developer for several years, switch to Firefox if you want to tweak anything that bothers you easily without having to change the damn source code.