STL is a simple 3D printing format (geometry only), OBJ is more powerful with textures and materials. STL is simpler, OBJ is more versatile.
| Criteria | STL | OBJ |
|---|---|---|
| 3D printing | ✓ | ✗ |
| Textures | ✗ | ✓ |
| Materials | ✗ | ✓ |
| Simplicity | ✓ | ✗ |
| Software support | ✓ | ✓ |
For 3D printing models, rapid prototyping, slicer software.
For 3D rendering, textured visualization, Blender/3ds Max.