Support infrastructure company Crittercism says that programs crash around 2% of the time on the 5S, compared to under 1% on the 5C or 5, reports All Things D.
The speculated cause of the extra crashing has nothing to do with flaws in the device, but in how prepared developers were for the new hardware on the
While developers could test their apps with an early version of the new iOS 7 operating for several months, they weren't ready for the new hardware of the 5S-in particular it's 64-bit A7 chip and speedier processor. The guts of the 5C are almost identical to the 5, so mastering iOS7 was effective enough.
At this point, Apple has already pushed two new updates for iOS 7.