I have owned many S60 devices, the first one by "accident", with the salesman warning me that it was "complicated" (which only intrigued me more so I bought it, a Nokia 6680).
Since that time, each new S60 phone I have bought has been not necessarily an "upgrade", but definitely a different phone than the previous model.
For example, the change from a 6680 to an N70 brought a better camera and better Internet browsing (memory issue).
The change from an N70 to an N91 brought a 4G hard drive, excellent sound quality, and a 3.5mm headphone jack.
The change from an N91 to an N81 8G brought a larger memory, gaming buttons, and a more convenient size and weight (albeit, the first time I had a feeling that build quality was going down instead of up, but not horribly).
Then, the worst switch of all, from an N81 8G to an N85 cracked D-pad, impossible to see outdoors screen, badly built slider, not-so-great easily scratched-up keypad, etc. So, for the second time it seemed, to me anyway, that Nokia wasn't going upwards with each new year's selection.
So, I chucked the N85 for an N95 8G. Well, unfortunately, it's been the best phone of all of these. I say unfortunately because I should be wrong about buying a 2-year-old phone being better than a (at the time) two-month old model. But I'm not. Now, when I see the new models coming out I just think to myself, "Wait and check all the online reviews, wait for the firmware updates, see if it has any horrible defect that everyone is complaining about, then if you decide to buy it one day, cross your fingers and hope that you don't get a lemon!"