Why browsers are "bloated and sluggish by design", is a myth, and just plain wrong. I just wanted to give you this example, especially because this topic has been discussed quite a bit on this board. The only reason I mention it is because if you look closely, most of the things that are said about modern browsers are actually true. As a consequence, I am not entirely surprised to see people on the forums complaining about this in terms of performance issues but I think it would be easier if we focused less (or even just less) on browser performance than on other aspects such as compatibility, security and usability.
We have a few reasons to use a web browser but I would argue that browser performance and compatibility are both far more important than just speed. As it is, most of the browsers out there have performance problems, some of them far deeper than others. However, browsers are always improving and when we see an improvement in browser performance we tend to applaud it as being significant. WebGL is becoming a serious contender for high-performance video, and it doesn't get any faster that using direct hardware calls. With that said, let's look at some of the major browsers and see what they are doing to improve performance and performance scalability (or in my case I mean performance of all their parts in comparison to each other).
Firefox : Firefox has an awesome WebGL implementation , allowing us to render any scene using WebGL with the ease of an app in modern browsers and it seems to go a bit faster overall, with less rendering overhead than Chrome. However, performance is still not perfect, and I think I'll stick to Firefox as my default browser for future web video work since it's a bit more mature.
Chrome : Chrome has a ton of WebGL support and it is very easy to see what the performance is about on various devices and the WebGL implementation works really well with some of these devices (a tablet works fine on me). It's not even as good as Firefox for video work yet - but I think that will change.
Safari : As a browser with some nice WebGL support, Safari has a very decent performance on a modern phone, laptop or web browser, but performance is not great when working with 4k at a higher resolution. The good news is that WebGL support is quite open.
Edge: Edge is the most basic WebGL browser and the reason for this is that Chrome and Safari both have their own open WebGL driver, Open GL, built in. There is also a newer version of Edge with support for WebGL but even so, it's still far behind Firefox.