ES6, or ECMAScript 2015, introduces several new features that enhance JavaScript code quality, including 'let' and 'const' for variable declarations, 'for...of' loops for easier array iteration, the spread operator for array and object manipulation, Map objects for storing key-value pairs with custom indices, and Promises for managing asynchronous operations. These features offer more control and flexibility, allowing developers to write cleaner and more efficient code. However, some features require polyfills for compatibility across different browsers. Overall, ES6 provides developers with tools to improve development processes, though not all features may be immediately useful to everyone.