Currently IrrNewt has these features:

PHYSICS FEATURE

-coupond collision body

-tree collision body (including terrain support)

-vehicle

-full documentation

-automatic creation of a body (takes lots of information from the scene node and pass it to newton. Also calculate automatically the correct offset if in your file the model is not centered)

-tree collision body serialization\deserialization

-ray cast related functions

-character control

-camera physics

-material support (including material callbacks)

DESIGN FEATURE

-completely OOP

-including high level functions (see for example CharacterControl class that provides functions that there aren't in newton or in irrlicht)

-design to build a good physics with little lines

LICENSE FEATURE

-open source and free to use in commercial projects (LGPL license)