Possible fix: Turn off Traffic, in location services. Settings > Privacy > Location Services > System Services > Traffic
For me, my iPhone 5 always freezes on the lock screen. I noticed that the loction services icon always seems to be present when it crashes. Perhaps just a coincidence, but I did a little sluething and experimented with turning off various locations services. Ever since I turned off Traffic (which was one that was being accessed in the lock screen) I've had zero freezes. It's been three days so far. I also have Frequent Locations turned off, although that was turned off previously and it still froze.
These are both features I'd prefer to use, so hopefully there's a software update in the future that fixes this. Otherwise, I'm looooving iOS 7.