Why UI Toolkit?
In summary, Unity UI (uGUI) is ideal if you prioritize familiarity or require 3D elements and custom shaders. UI Toolkit is the better choice if you need scalable, high-performance layouts with modern styling options.
Unity's comparison
Unity's Comparison Comparison
| Subject | Unity UI (uGUI) | UI Toolkit |
|---|---|---|
| Architecture | GameObject-based, with each UI element as a GameObject and Component | DOM-like visual tree (similar to web) with no GameObject overhead |
| Scalability | Prefabs provide reusable UI elements but can become cumbersome to manage, especially with complex nested hierarchies and style adjustments | UXML and USS enable reusable, modular UI components with styles applied globally, making it easier to manage and update UI elements consistently across the project |
| Performance | Higher overhead with many UI elements, due to GameObjects and RectTransforms | More efficient due to lightweight visual elements and optimized rendering |
| Layout System | Uses RectTransforms and anchors, which can be tricky for responsive layouts | Flexbox layout, more intuitive and powerful for dynamic, responsive UIs |
| Styling | Customization done through scripting and component adjustments | USS (similar to CSS), allowing for powerful and reusable styling |
| Ease of Use | Familiar GameObject workflow | Declarative UI (UXML/USS) more complex but promotes cleaner separation between logic and style |
| Editor Experience | Visible and manipulable directly in the Scene view | Integrated tool called UI Builder |
| Textureless UI | No | Create visually appealing UI without relying on textures |
| UI positioned and lit in a 3D world | Yes | Possible to via render textures, but cumbersome to work with. (This feature is currently in progress.) |
| VFX with custom shaders and materials | Yes | No |