TrueEngine is an actual game engine.(though i dont like it), it has a lot of other classes and components builtin for models, sky boxes, particle systems, etc...as it stands, XNA Framework or GSE don't have those luxuries. XNA right now is just a framework, the structure of the game is pretty much already made, and you can get in to making game logic, etc...pretty fast. But they'll be adding more things over time, so we'll see.
how low level is XNA
BBBXXX
theTroll
mattdawg