This pack goes to show it isn't easy doing flat design.
The colours/typography are pretty off and there's alignment problems throughout these free PSDs. The user profile/siderbar templates are especially bad.
Flat design can look bad in the wrong hands just as much as skeuomorphic can, it's down to the designer
If you want to see a nicely curated set of good design for iOS, go here: http://pttrns.com/