WebGL:

· WebGL allows you to control the GPU in more direct way

· It is more an “immediate mode”

· It does not have additional support for text, for shaders built, for picking, etc.

Three.js:

· Three.js is built on top of WebGL and allows you to take care of lot of things like what objects to draw each frame

· It is more a “retained mode”

· It does have an additional support for text, for picking, for object hierarchy, etc.