Moved to mobile app forum.
I didn't realize there was yet an iPad 4, I thought there was the "new" iPad (iPad 3) and iPad mini...but I'm lucky I know the iPad exists.
As far as apps, free I like Medscape because you can download full content and not require internet/wifi access later (aside from photos that require internet access) there is also Micromedex Drug information and MPR for drug information. Skyscape has both paid and free components to the app. I also like the free ARUP Consult for lab information.
Nursing Central is a pad app but with many resources (not cheap but if you elect to not renew, you can access the resources until you delete the app but cannot update the references until you renew the annual subscription)
As far as apps I use with my patients, as a pediatric nurse doing skilled home health/PDN I don't use medical apps but more cognition and functional apps like drawing, Sound Touch, speech buttons, MusicColor, PaintSparkles, DoodleBuddy, Disney apps that correlate with my patients' therapy objectives. MedScape, Skyscape and the free version of epocrates (on my iPod touch) have been helpful in multiple situations to check drug calculations, review condition information/parent teaching, review drug information for parent teaching. Not to mention the calendar and to-do list apps for keeping my own life in check.