I like them a lot and have used them a lot in the past. I think my first Nostr prototype used SSE, but then I realized it would be simpler to do WebSockets in the Nostr case specifically, i don't remember why. Another factor was that given that SSE is less known and somewhat mysterious (despite being super simple) library support is worse (according to my own past experiences dealing with SSE in Python, Go and React-Native).