My take has always been that the 820 was a mistake by Nokia. Of all their models, the best offering was the 720, unfortunately. It is a nice phone, don't get me wrong, but when Nokia tried to fill out their rang with the 720 and the 820, that was a bad move. It is like they split the 920 up features wise and gave the 720 the good design and great camera for its class, gave the 820 the very good display and neutered the internal storage.
I enjoyed my 810, and I liked seeing the 820/822. But, once they didn't sell in the US, that was that. What Nokia forgets is that the prices of their phones don't drop as quickly. So I would often get these knuckleheads on WPC who would preach to me how much better the 820 was vs a Ativ S at the same price point in some markets - like you can physically use Nokia's "aftersales support" as a space to load more apps on when you physically exceed your internal storage.
I hope Microsoft doesn't make the same mistake as others before them and put put ether good value for money entry handsets and great hgh end models ONLY.