Re: 75%?
It sounds like you are getting this phone confused with a Windows Mobile 6.5 device. It is not everyone's cup of tea, but that is preference, not driven by actual facts.
The UI is slick, fluid and responsive. I own, and use daily a Nokia Lumia 800, iPhone 4 and an Android device, they are all good and I would be hard pressed to chose between then, but WP7 (especially the 800/900) is a worthy contender.