John Gruber makes some interesting observations about the differences between Apple UI and third party developers.
Exquisitely well-done new drawing app. Note the complete lack of persistent on-screen UI chrome — there is a fork in this regard between Apple and third-party iOS developers. Cf. Clear for another recent example.
The tension is between simplicity and obviousness. Eliminating on-screen chrome is simpler, more elegant and beautiful. But Apple’s use of minimal but persistent on-screen chrome makes things more obvious. Big differences can result from a slight shift in priorities: simple and obvious vs. obvious and simple.
(Via Daring Fireball)