Unlike my 'normal' self, I don't feel compelled to list ALL of the reasons I've switched from Mother Chromium to her rebellious Opera offspring. I've been down this road before, going well into the last century. And, it's a great way to start a flame war...
It probably wouldn't make sense anyway, unless you're a professional psychiatrist or web developer.
Suffice to say young n' beautiful is better than old n' ugly. I judge that's reason enough for the vast majority of ordinary users. However, in a pinch, kludgey old Chromium will fit the bill for doing what's required, not to mention its unbridled and growing popularity. That's some of the reasons it's included in Peppermint, by default.
I keep Chromium around for placing online orders, then sanitize it when I'm done, and put it back in the drawer for the next time. That way, i don't need to worry about what Opera is giving up, when I turn off their free, unlimited VPN service.
I 'drank the Mozilla Kool-Aid', as you put it, for a few years, but gave up on Firefox @ ver 3.6. I've tried to love it since - really, I have - but it repulses me these days. They need to purge it and start from scratch IMO.
That said, I still love Thunderbird (basically the Firefox browser haxored into a delicious mail client suite by volunteers). OOTB it's as butt fugly as Fx, but easily corrected with the 'Theme Font & Size Changer' add-on, and various tweaks in the 'Thunderbird Preferences' section.
Chromium offshoots are the way of the foreseeable future -
look at the global web stats.. Resistance is futile.
Your pick appears to be Google and friends , which I wouldn't touch with a 10-foot pole, but to each his own. Buy a Apple X 'smart' phone (facial recognition logon), get some microchip implants (no more credit cards and door keys needed, et cetera) and enjoy yourself.
