Both were beautifully designed phones, with a unique and powerful operating system: swipe-based interaction, social feed screen, multitask, beautiful applications, good development environment (Qt).. This was the direction Nokia should have gone toward..
Edit: typos.
I somehow get 1.5-2 days use out of the thing, per charge, despite frequent multitasking (browser, SMS, notes, ssh etc.) and typically running it with a slight overclocking to 805mhz. A script switches on airplane mode while I'm asleep, so that probably helps.
Others have mentioned the screen, but I'm really comfortable reading on it. The Opera browser makes the peck and hunt game on desktop versions of sites obsolete. All the fuss about resistive/capacitive differences is beyond me. It's really quite easy to move (things) about on the screen, and I'm not into splitting hairs.
Some have mentioned the Psion series in this thread. I have to agree, the 5MX was a brilliant design for a mobile device. If that keyboard was coupled with modern, open HW in a similar phone it would be game over. For me at least.
I have been considering buying a folding bluetooth keyboard to type up notes and posts on the phone, but I think that's pushing it - my main 'creation' work still happens on the PC, for better or worse.
I don't do a lot on it that you can't do on any other phone, but it does give me a warm feeling that it's at least open and not phoning home at the end of the day to update Sauron.