Just my personal and non-expert opinion, but based on Apple's own apps, all solid but lacking more advanced features, their apps are fast and efficient, but as far as more features (more useful features at that), they've Bern outdone in just about every category.
Pocket Informant outclasses iPhone's calendar event in everything but speed.
A lot of weather apps provide far more detailed reports than iPhone's weather app.
iPhone's Note app can't even compare against apps like Notebook, Momo, and others as well.
I use Picture Safe in place of the Photos app...
In short, I believe Apple will eventually build a very solid if basic app for editting docs one day, but it'll always be behind other apps in terms of it's ability to perform various functions.
In terms of apps, Apple's a fairly good Jack of all trades but definitely a master of none IMO.