Speed is not everything to me.
I like some degree of control with my browser, be it fine grained cookie control, stopping videos autoplaying, script disable / whitelist , tracking disable, inspecting traffic / scripts (when debugging web apps) etc.
Which, typically means a browser with a good ecosystem of add ons.
So, depending what platform I am using / where I am , I use a variety of browsers, depending what's appropriate (e.g. if using dubious hotel WiFi I may well use Opera to make use of inbuilt VPN)
If some sites misbehave with a particular browser I will drop that site a line (if they actually provide contact details).
Don't like the idea of being resolutely wedded to a particular browser (though usage based probably use a couple of Mozilla forks most frequently just because of add ons). Use chrome sparingly as I find it quite a resource hog & annoyingly busy at writing to disk when it should be doing nothing