It's getting there! They finished a rewrite of the extension recently and it's quite nice.
If you're on Windows like me, sadly there's still a nasty bug with path mismatches between the LSP server and the VSCode extension (https://github.com/denoland/deno/issues/9744) which requires reloading the window to fix spurious errors, but I'm sure it'll be fixed soon enough.
Jetbrains extension hasn't been updated much since release and doesn't interface with the official LSP. The experience is poor and outdated.
Vscode extension is maintained by the official team and will provide the best experience. There are unofficial plugins for sublime and Vim. They use LSP too and provide a comparable experience.
If you're on Windows like me, sadly there's still a nasty bug with path mismatches between the LSP server and the VSCode extension (https://github.com/denoland/deno/issues/9744) which requires reloading the window to fix spurious errors, but I'm sure it'll be fixed soon enough.