This is an interesting thread. I've been trying to work out whether it's worthwhile updating my Edge Touring Plus, which is, I think, of the same generation as the Edge 800. On the whole I think it's still fine for Audax, but I'm developing more enthusiasm for activity/mileage tracking after being bought a wrist tracker (for walking etc.), and because my club runs a low-key competition just for fun.
So, whilst I looked at the 530 and 830, I'm thinking that something simpler, such as a 130 or even a 25, might be better to have routinely on the handlebars for utility riding. More affordable too. But thoughts welcome.