Very interesting aspects, thanks.
There's another aspect for me, which is using my device 1-3h per day for talking on the phone as a project manager. So I expect from the phone side has to be good reception, good voice quality, no freezes, and moderate level polished user interface. This is during worktime.
Then when work ends, in my freetime, and when travelling, I think, if I have the N900, I would use it for a lot of things I don't do now, but I would enjoy exploring, connecting with VNC to my home PCs, lot of web browsing (anything that I need to open up my laptop to order pizza, internet banking, buying movie tickets, look up movie stats on imdb, light photo editing, managing databases in Excel, etc.).
I don't know how would this interfere with my down to earth style calling needs during work hours.
If my device becomes unusuable, or messed up, that is not acceptable. What is installed and runs, it should work error free. This is where my Treo 680 fails -poor voice quality, no receptions in weak areas (where my Nokia 1600 barebones phone has 1-2 bars), occasional freezes in "on the air" situations.

@sljonson
What is Evolution? Can you give a website?