The idea of doctors using iPads scares me; I know plenty of people who make casual typos with numbers on the iPhone or iPad as it is -- the last place I want someone doing that is in a hospital or doctor's office.
You bring up a really good point. Moving to electronic systems has both huge benefits and some risks that have to be mitigated.
An example of a huge electronic benefit you can't get on paper charts is drug interactions. drchrono can automatically check drug interactions and warn the Doctor in realtime based on latest available clinical information and drug warnings. My parents take 20+ prescription and non-prescription drugs each, there is no way even a genius Physician would be able to process that number of associations at first glance of a paper chart.
The risk of misentered information being accepted as factual because the computer presents all information in the same way is a very real risk that has to be addressed and have safety nets put in place to scrub and check for these errors. One cool way we are tackling this problem is launching an industry leading speech to text processing system in the coming weeks. Letting Doctors record their notes and have an automated transcription can give a safety net for errors.