My first reaction was "I think this is just Dungeon World again", but that was wrong.
6e is a clever boil-down of mechanics from DW, Blades In The Dark, 5e, and I swear there's also some Into The Odd in there. It takes a kind of "I can't believe I'm doing this" tone to its own design, but it's also really tightly built.
There's some mechanical elements in 6e that might not be everyone's thing, such as rolling random for stats, but it's also very upfront that it expects you to mod it and change the bits you don't like.
You *will* need to freestyle your own adventure or use a module if you just pick up and play this, as it doesn't come bundled with one, but teaching the game and setting up a character takes like ten minutes tops.
On top of that, the classes all feel solid, and the character sheets are probably some of the easiest to read/use that I've seen in any system.
Honestly, I can see why 6E is the world's most popular roleplaying game.