8 year old tablet is not a fair competition, is it? I can dig out my old Windows 98 machine and try loading some websites on Internet Explorer 6. This wouldn't tell me anything else than - well, IE6 sucks.

JetStream benchmarks evaluates how well/quickly the browser performs doing certain tasks, like crypto, loading external libraries, 3D rendering, physics, basic algorithms like Fibonacci numbers. More is better. In-depth analysis of each step, including source codes for the programs that were ran during benchmark here: https://browserbench.org/JetStream/in-depth.html
I know it's a bit specific and doesn't necessarily reflect how you'd use it in real life but it serves as a nice indication of how well JS engine of given browser performs doing various tasks.

That's why I also ran Web 3.0 Basemark, which evaluates WebGL, Canvas, SVG performance, as well as HTML5 support. Again, higher is better.

Too bad, it's already there, the difference is that if you then rapidly scroll up, SFOS browser shows some blurry mess from cache. I have no such issue on my PC though, but then I use one of these webkit browsers :/

Web has changed since 1980s, guys. You might not like these shiny, constantly refreshing, responsive websites, but they're here. According to StatCounter data this release of Firefox is in use by ~3% Firefox users, you can't expect web developers to jump through hoops just to support it, you know. Not being supported by an ancient browser doesn't mean that website is not coded according to standards, it just means that the browser is not supporting them.