I gotta be honest, the only reason I use FF is because of tab tree extensions. I usually defend it for that reason + some privacy benefits but I do all my professional work in Chrome because it's way more popular and I grew up on it's dev console. If Chrome supports tab trees I'd probably move over so I can do less context switching.
FF is more than that. It has multi account containers, which lets you work with isolated browser sessions — super useful when you have to login to multiple accounts.
I switched form Chrome to Firefox some time back and have no regrets. I was ready to be the outlier but to my surprise FF is well supported in the BigCorp tech company that I work for. (Native internal addons are still being developed)
Chrome is not bad but it is not better than FF for the things I’m doing.
I think we also live in a world that is different from the world of IE6 which had a lot of vendor specific stuff. The web today—though not perfectly vendor agnostic—is much more so than before.
Split tabs also exist in Vivaldi. I do think it would be nice for Mozilla to invest seriously in features like this, but Sidebery, Tridactyl, and especially UBO are frankly sufficient reason for me to stick with Firefox.
