5098 is incomparable as far as historical significance and incredible dial is concerned (just my feeling of course). It’s also smaller and an overall slightly better fit for my wrist. But of course 5100 is more modern looking (nobody would call it a “dandy watch” as Count de Monet said for the 5098) and has a unique manta ray case shape. The movement is larger too (the 10-days is a technical prowess, but I don’t care too much about this aspect because I like to wind a watch daily). And both share the same drawback, even if it’s for slightly different reasons: the winding experience isn’t delightful, which I regret (compared to the pleasure of winding the Cornes de Vache, it’s simply not on par, unfortunately).