It's not perfect by any means, but it is now my favorite :)
Edge put together a really great visualization of the API surface of all the browsers. - https://developer.microsoft.com/en-us/microsoft-edge/platfor... The API surface (and bug surface) is actually pretty different these days.
Internally Blink and WebKit are also diverging reasonably rapidly. As a specific example here is the project to re-architect how blink does it's painting: https://www.chromium.org/blink/slimming-paint
EDIT: spelling
Not quite - those that employ the maintainers define the standard, as shown multiple times by Red Hat (multiple projects) and by Apple with WebKit.
IIRC, before the Blink fork, Google was pushing more commits into WebKit compared to Apple, but there was a - let's call it a difference in perspective - on a feature a Google employee wanted to implement, someone with an @apple.com email said "no". I can't remember what the issue was, but this development unfolded on webkit mailing list.
Most things based on Chromium also use more components of the Chromium stack than just Blink. For example, in WebKit multiprocess support and sandboxing is provided at a batteries-included level. But Blink just has the hooks for it, while the actual implementation of the process architecture is done by other aspects of Chromium.
This is not to say one way is better or worse, but rather that there's significant differences between being WebKit-based vs Chromium-based.