I've been happy using my A15 + XBA-A3 for the past year, but as usual upgraditis has me looking for the next step up. Is everyone still happy with their ZX100? Apart from better sound, battery life and so-called DSD support, any other pros over the A15? Any negatives to consider? What's the navigation pad like? I really dislike the awkward triangle shape of the A15's buttons, and thin back button. Thanks in advance.