The biggest difference in appearance has been the screen - the clarity and sharpness is a street ahead of my old iPhone 3GS. The latest iPhone 5 may have a better screen than the 3GS but the Nokia Lumia 800 still compares very well.
So far the biggest positives have been:
- Excellent screen, both resolution and clarity/colours
- Spellchecker and autocorrect far more useful than iOS/iPhone
- People hub to connect social activity is fantastic and the level of integration is great
- Group texting! Something that was never possible on iPhone. On Lumia, create a group and choose whether you want to email or text the members - simple!
- Limited apps eg no Dropbox
- Fonts take some getting used to
- Screen actions differ to iOS/iPhone eg hold to delete
- No dedicated silent button as per iPhone