Word translation into Pages is good, but hardly flawless. It can't be flawless because Microsoft's file formats are proprietary, so we're always relying on imperfect reverse engineering efforts. Pages will fail to import text boxes, character shading (whatever that is), and sometimes tables (accurately) from Word, and will reject some older Word documents entirely.
The biggest problem I've got importing Word documents into Pages is the lack of discipline most Word users seem to have in creating paragraph and text styles. I've seen as many as 50 styles applied to Word documents. Yeech. Maybe that's a product of Word's confusing method of defining styles. Fortunately, Pages makes this mess pretty easy to clean up.