Samsung Internet beta now works on most Android devices, not just Samsung's
Samsung Internet running on an LG G6 in high contrast mode
However, support for non-Samsung/Google devices is limited to the beta version only, though it should eventually make its way to the stable branch as well. Samsung hasn't given a concrete timeframe yet, but it's worth noting that Nexus/Pixel support only made its way to the stable version a couple of months ago, which doesn't inspire much hope, but we'll see.
But besides this, the v6.2 beta adds a few more interesting features. The most notable of these is the high contrast mode, which enables for easier reading for visually impaired people (and is a separate option from the existing night mode). But alongside it there's an upgrade to a new, snappier version of the Chromium rendering engine, as well as several more experimental features like WebVR support for Google Cardboard and the ability to control Bluetooth devices right from inside the browser.
Things that are NOT allowed: