I can’t find any downsides of SSE presented. My experience is that they’re nice in theory but the devils in the details. The biggest issue being that you basically need http/2 to make them practical.
Take this for what it's worth, but I see you share rupy on pretty much every thread that mentions WebSockets, and I click on the link pretty much every time, and I still have basically no idea what it is. Documentation probably isn't your priority at the moment, but even just a couple paragraphs could go a long way.
I had the same impression as you. I want to learn more about fuse but even their "sales pitch" page is in the same tone of "fuse can do a lot" (and that's fine, I'm sold!) except there is very little documentation at the moment.
I know, I just go by "the code is so small, you should have time to read it".
rupy is a minimalist, from scratch, HTTP app-server that uses non-blocking IO so it can scale comet-stream (SSE or not) which is much better than WebSockets: https://news.ycombinator.com/item?id=30313403
I will never make projects that you just download and double click to run.
I want my users to understand how it works more than I want them to use it!
https://github.com/tinspin/rupy/wiki/Comet-Stream
Old page, search for "event-stream"... Comet-stream is a collection of techniques of which SSE is one.
My experience is that SSE goes through anti-viruses better!