Ranked in these QuestionsQuestion Ranking
Pro Pretty fast
Compared to emacs-eclim, this feels very fast, even over ssh X11 forwarding.
Pro Almost sufficient to replace the IntelliJ frontend
You can toggle the IntelliJ GUI on or off with M-x lsp-intellij-toggle-frame-visibility which helps smooth over the parts which aren’t yet strong enough from Emacs.
Pro Uses IntelliJ backend
Con You must have IntelliJ IDEA installed to use this mode
Since the internal API directly communicates with IntelliJ IDEA, you must have it installed to use the mode.