The desktop version of Deluxe (CD/download) has some additional advantages in its features, too, while Online Deluxe has some limitations as discussed below.
Desktop Deluxe can prepare multiple Federal returns with up to 5 free Federal eiles. Online editions can only prepare 1 Federal return per account per year.
Desktop Deluxe has the popular Forms Mode for direct viewing/printing/editing of forms during preparation. Online editions do not have that feature.
Desktop Deluxe can prepare all the usual Federal forms. Online Deluxe cannot prepare Schedules D, E, F, or a Schedule C with expenses, and it cannot enter a K-1.
