Cheers folks, glad you see it as useful.
@ArniVidar - shouldn't need to cancel out of the sync process, because you can always "re-link" a book, regardless of whether it is already linked or not from that screen. Anyways, hopefully you find a workflow you are happy with now.
It can still get a little clumsy when you already have a book added to your Goodreads shelves and then want to switch editions, but I don't have a solution for that (other than get the edition you want right before you start syncing it anywhere else!).
So I see this feature as probably most useful to someone using the latest (beta) of the Count Pages plugin, where you don't have the book on any Goodreads shelves (may not even use Goodreads shelves for that matter) but do want the ability to switch to an edition which has a page count. Or equally for someone who has not yet added a book to their shelves and wants to refine the match.