I have no preference, really.
I can work with your final version… or one chapter at a time, after your adviser returns each chapter with comments or requests for revisions… or as you write each chapter (i.e., I can edit each chapter before you send it to your adviser).
Some thesis advisers prefer that their students work with an external editor during the writing process.
This way, I ensure you’re on track, that you understand what your adviser wants, which saves you time, keeps everyone happy — and you get to graduate as planned (or earlier than others!).