I've been using the Zen Browser for a about three months now, and it has done what no other web browser has been able to do for more than a couple of decades. It took the place of Firefox as my go to web browser, something that until a couple of months ago seemed unlikely.
To be honest, it helps that Zen is a fork of Firefox. It allows me to use my Mozilla account, which made the transition easier. Not only that, all the it feels a lot more modern and supports Firefox's add-ons. The only thing that it doesn't is Firefox's themes, but for me is not a big deal since Zen looks a lot better for me out of the box, and it just takes some tweaks to make it feel my own.
It also helps that it is a free and open source app, which I prefer over proprietary apps where is possible.
Honestly, I made the jump not because I didn't like how Firefox has changed with time. I just found that Zen comes closer to what I want my web browser to look and behave. And it helps that it not only a fork of Firefox, but its updates continue to have Firefox as a base.
Now, the browsers I can recommend are Firefox and Zen. Both are fully free and open source apps, with different take on how to implement a web browser, as such they target different people as an user base. Most importantly, along with other Firefox's based web browsers like LibreWolf and Waterfox, gives users alternatives for web browsers not based on Google's Chrome.
Personally, I see Firefox and Zen as the best options for mainstream users, or users that just want a web browser that with a focus more on their needs. Though I'd say that Zen is a bit more privacy focused that Firefox is nowadays.
Now, if only Linux Mint developers would allow to make web apps based on Zen it would be great...