One thing I really like about iPhone is the ability to change the SIM without a reboot.
Its so annoying that Nokia always puts the SIM under the battery.

But mostly I just miss a decent mapping app (google maps), and calendar/contacts sync that works.

The iPhone even has a much better command-line environment, including zsh.
(No point comparing n900 to an un-jailbroken iPhone, is there?)

But all is forgiven when I use the web browser.

I see this is your first Maemo device :-)