I was hoping that the free version + IAP would generate significantly more revenue than the paid version, since I've read so many articles claiming that freemium is the future of the app store.
So far this hasn't been true though. Currently IAP revenue from the free version tends to be about 1/3 the revenue of the paid version even though free app downloads outnumber paid by at least 10 to 1 on most days. It does seem like IAP has been ticking up a bit over the last few weeks though. Maybe people have to play with the app for a while before they're willing to pay for it?
Personally I'd prefer to just do paid apps, since adding IAP + store transactions adds a fair bit of work.
I really wish Apple would just implement a trial period like Google's Play Store. I understand that people don't want to pay for an app without trying it but trying to solve this problem with IAP just pushes this responsibility onto developers and results in a more confusing and inconsistent experience for users.