Just stumbled over this thread and I must say, I just love the talk about opinions and the right and wrong thing and such
Opinions are just opinions. I wouldn't take any of them as an offence. There's no right, no wrong. The only device necessary for a person is the one which suits the persons needs.
I have a 505 which I love for its display. It has tradeoffs though. I passed it on to my wife and she's similarly enthusiastic about it as I am. I switched to the 600 for several reasons already explained. I love it for its features the 505 didn't have. It has other tradeoffs that the 505 didn't have ;-)
Ok, I also wanted to just give my 2 cent.