I am observing that whenever I am profiling my application using instrument in Xcode 6.0.1, application hangs every time while I am browsing through the application. I am using iPhone 5S (iOS 8.0.2) to run my application. When I run the application on device it runs all fine.
Found the fix - disabling the NSLog statements (profiling on release and not on debug) solved the issue for me.