You have to keep track of what each tab contains every time you need something. We have seen this at work and it's always fun to see certain people who keeps clicking on tabs in order to find out where their stuff is.
...and how much longer would it take them if they had to keep track of the info in those tabs some other way?
Anyway, is the iPad really that different from the simulator? It was pretty easy to open "new" windows in the sim, so it had about 80% of the functionality of tabs built in.
