SQL Server Profiler = awesome. You can basically say "record every query that's going through the server for the next 15 minutes" – and then rerun those queries through a planner (SQL Server Tuning Wizard) to see where you can optimize them by adding certain indexes, etc. It'll even suggest indexes, etc.

So you could basically trace a production workload and then tune it offline.

Doing things like backups in SQL server using the agent, and running various workflows, also works really well. To this day, as far as I can tell, doing backups for most open source databases are a hodgepodge of bash scripts, cron jobs, and *dump executables, which every admin reinvents every single time.

These are all GUI apps that, albeit have barely been updated in a decade, but still better than most first party (or even third party) open source DB management tools out there.

I've heard all the high availability stuff is really good too but I've also heard that it's a pain to setup and until recently, only available in the really expensive enterprise license.