Initially I was partial to the 35mm Saxonia but if you place both watches side by side, you will notice that the patina on the dial of the ultra thin is more vintage looking/ richer and blends well with the rose gold case. And the 37mm ultra thin is a much better looking watch than the 40mm ultra thin. The reduction in size was important because the ultra thin is a two handed watch with relatively a lot of empty space on the dial so the larger the dial, the more empty the watch looks.