Not only is it very similar but, unlike Chrome or Safari, every aspect of it is customizable so you can make it look however you want. Out of the box you can rearrange the the UI elements to match Chrome or Safari.
https://addons.mozilla.org/en-US/firefox/addon/custom-tab-wi...
I tried breaking the habit for a while but I ended up opening FF all the time by muscle memory.
I'm also a fan of minimal as possible.
Nothing fits better next to a terminal window or a code editor.
I know that all that maybe sounds rather petty and maybe there's something wrong with me and it's my biases for some reason, but it just all adds up to a fuzzy notion of childishness and less than "down to business" feel. I say that as someone that used to exclusively use FF and shunned Chrome for all the various reasons mentioned by others.
The new FF UI has been out and stable for nearly two years now.
And now that I think about it, it's even things like the tab behavior where Chrome condenses tabs and FF just pushes them out of view an adds the disgusting scroll UI. Maybe that's a personal preference thing, but I would very much prefer having a dense overview rather than having what is essentially a nested scrolling.
More seriously, FF's dev tools have felt more advanced than Chrome's for a while, including the ability to edit and resend an XHR request.