I'm thinking of buying a 620.
They look great in the shops and the reviews look really positive online too.
However, as with all of these things I want to keep it looking as pristine as possible and the idea of being able to buy a replacement back cover, should the original become damaged, without having to buy an extra protective case is a major plus.
However, it's heavily advertised that different "shells," are available, but not as easily as I would like, though I'm grateful for some of the suggestions on this forum.
Nokia themselves, IMO, should supply them at source, which would make life an awful lot easier.
And, so far as their "support," pages are concerned, as with many of these companies, they don't seem to make it that easy to contact them.
So, I may end up sticking with Android when I upgrade my phone in a few weeks..
At least with Samsung, you can get in touch with them pretty quickly and they're pretty quick at responding.