I know a lot about the N8, in short -
- Industry leading mobile phone camera
- 'Proper' sat nav that doesn't require a mobile data connection, so useful abroad or if you're in the countryside with no signal
- Symbian, while ugly, has a lot of functionality
- Will improve significantly with the Symbian Anna update
Bad points -
- Symbian is ugly and a lot of people hate using it
- Screen could be considered a bit small if you browse the web a lot
- Relatively inferior app store, though there are some good ones
- Video recording isn't as good as you might hope given how excellent the camera is
- Things like the web browser that you may take for granted are a bit rubbish, but you can get Opera and other fairly decent alternatives
As you have a San Francisco, you know what Android is like, but in all honesty, I only think Android is excellent on decent handsets, I wouldn't be at all fussed about it on a phone like the San Francisco. Out of the two, I'd have the N8 by a mile.
Having said all that, the Samsung Galaxy S II is the 'best' phone out at the moment, some people moan about it's plastic body but it is just plastic to make it light, the grade of plastic is very high and the actual build quality is easily as good as Nokia and HTC phones. If you don't need a lot of minutes you can get one for £21/month for 24 months on O2.
With that you have Android, which is superior software on the whole and a camera which isn't really far behind the one on the N8, certainly more than good enough for what most people need, a much larger and better screen, similar (possibly slightly inferior) battery life, and the best 1080p HD video recording, if that's important.