The Goûter route is spectacular, varied, and enjoyable from start to finish. I had wondered whether the route was popular solely because of its accessibility, its relatively low technical difficulty, and the fact that Mont Blanc is the summit of the Alps (4808 m). Not so, this route is great (even better without the crowds) and I recommend it.
This mountain definitely merits a return visit, either via the Goûter route in summer, via the Grands Mulets route on skis in spring, or perhaps from l'Aiguille du Midi across la Traversée des Trois Monts...
In retrospect, one additional night on the mountain would have helped our chances of making the summit. A good autumn itinerary might look something like this: day 1 up to Tête Rousse, day 2 up to Goûter, day 3 summit and descent to Tête Rousse, day 4 descent to Les Houches.