I don't want to customize the visual appearance of my browser because I find that a waste of time.
For this reason I want a browser whose default settings and appearance are good to me from the get go, this way I can install it and use it in all computers I normally use (quite a lot) effortlessly.
Also, if it is a well known browser, so that IT doesn't bark at me when I want that on my PC, then better.
That said I need to be able to customize the behavior (not appearance) of the browser through add-ons and/or scripts. This is relevant for me, a good support for additional functionality, i.e. ad-blockers, miner-blockers, greasemonkey, rss-feed readers, etc.
Another thing I want is a web browser that offers good support for debugging web pages. And also a browser that is fast, specially executing Javascript code.
For all those reasons I would either choose between Firefox and Chrome. Firefox has a better wider add-ons support IMHO, but Chrome is (at least in my experience) way faster executing Javascript. And that is the reason I usually use Chrome.