According to a recent report, apps crash on the iPhone 5S at twice the rate of those on other iPhone 5 models (this includes iPhone 5 and iPhone 5C). Now, before you worry too much about that, it’s not as if the crash rate is all that high to begin with.
Here’s a portion of the report:
“programs crash about two percent on the iPhone 5s, as compared to just under one percent on both the iPhone 5c and iPhone 5.”
Another reason is that this is new hardware. As the report says, developers had the opportunity to test their apps on the iPhone 5. The iPhone 5C is pretty much the same hardware with a different skin. However, the iPhone 5S is a new 64-bit A7 processor and the M7 coprocessor. In other words, it’s a very different machine on the inside.
It’s likely nothing to worry about, and should be resolved as Apple updates iOS 7 and as developers fix any bugs in their apps.