Nielsen has a few things to say about usability and iPad. One choice bit reads
iPad UIs suffer under a triple threat that causes significant user confusion:
- Low discoverability: The UI is mostly hidden within the etched-glass aesthetic without perceived affordances.
- Low memorability: Gestures are inherently ephemeral and difficult to learn when they're not employed consistently across apps; wider reliance on generic commands would help.
- Accidental activation: This occurs when users touch things by mistake or make a gesture that unexpectedly initiates a feature.
But seriously, you know you’re going to download and read Usability of iPad Apps and Websites: First Research Findings, the Nielsen Norman Group’s 93-page initial report on iPad usability.