Baron, you've hit the nail on the head. The proportions of the 5110 seem preferable over the 5130 (and each subsequent iteration) because the 5110 came first and remains the standard bearer. Like many, I have a strong preference for the 5110. While I find it nearly perfect, if I'm honest with myself I'm sure that I would feel the same about the 5130 had the 5110 never been borne.