A couple of things off the top of my head.
— advanced refactoring for all supported languages: implement interface, extract interface, automatic "generification" for methods and classes, stuff like that. Saves quite a bit of manual typing.
— built-in database client (which I have already mentioned) which also provides autocompletion for database/table/column names, both for SQL queries, and various supported libraries like ORMs.
— navigation (jump to definition/declaration, find all references, etc.) works everywhere: any supported programming language, XML, files like JSON schema, YAML, you name it. For example, you can put the cursor to a primary key of a table, press your "find all references" shortcut, and it will show the list of all foreign keys referencing that primary key. Same with things like URLs on the client side (for example, the first argument to the browser's fetch() function) — put the cursor on the URL, press "jump to definition", and it will jump to the controller method that implements that URL, including the correct HTTP verb if there are multiple method for that URL. This is just one example, there are dozens of little things like that. All that makes it much easier to work with fullstack projects (to me at least).
— the UI and its "control interface" (so to speak) is consistent. For example, you use the same key combination to jump through search results, list of issues, list of references, etc. etc. Same for other key combinations — they jump make sense, you press what you think will work and it usually just works.
— it also supports fuzzy search everywhere, not just in the command palette. For example, you open up the list of databases, start typing in the name of the table (or database, or foreign key, or procedure, or whatever), and it highlights matching entries and lets you jump between them. Press Up and Down to go though its suggestions. The same mechanism works in filesystem tree, search results, issue list, and so on.
> JetBrains UI is downright cluttered
All of that can be hidden. I have the filesystem tree to the side, the main editor taking 90%+ of screen real estate, and the tab bar on the top, everything else is hidden behind a keypress.
> As for keyboard use, the command pallete (Ctrl+Shift+P) is right there and should be able to do anything
This is not the same at all. Everything can be done through keyboard shortcuts without typing in obscure commands (even though fuzzy search helps, it's pretty slow).
You should use what you think is convenient, I'm not forcing anyone. The more pressure you put on JetBrains by using the alternatives, the better for us.