I'm curious, why do you feel you cannot abandon Chrome now? The only real difference I ever see between Chrome and Firefox (I use both daily) is that Chrome has less useful extensions and is blue.
Chrome is a little quicker and prettier. That's it, really. I've actually been using Vivaldi lately.
Vivaldi looks interesting, but I don't really trust anyone who has had any involvement in Opera... Opera could be good at times, but they consistently made poor decisions. One example, putting ads inside the browser itself. As for quickness, after using uBlock (with default deny) on both, and NoScript on Firefox, they tend to be equal. I know Chrome has script blocking plugins, but they are never as good as NoScript.
It is. Some of the features haven't been implemented yet, but it looks promising.