I own a 4s and am disappointed that Apple really didn't upgrade anything. It's the same stale size and features with a fingerprint scanner. Yes, I understand that it's now 64-bit and faster, but it will take another year or so to even be able to take advantage of this — just in time for another upgrade.
The 5s is just not worth the upgrade, IMO. There are better options now out there.
get ready to duck !
There are plenty of other smartphones, but they don’t work as smoothly as the iPhone.
Used to be a Droid fan, but I am content to lose Flash on my iPhone 5 since it actually runs well, doesn’t lag or lock up, and is reliable.
My previous Android devices were all cheap pieces of junk that were slow despite having all the right specs.
Apple may not offer the moon on their devices, but they take the time to make sure it works.
Samsunk and Motorolled don’t.

As for upgrading? No. I am fine with the 5. That’s the nice thing about the iPhone and Apple in general, including my four-year-old Macbook Pro.
They normally (unless you do something to screw them up) run almost like new for years.
My Dells and Gateways would slow down to almost unusable speeds after about two years of use. And yes, I have virus software and wasn’t doing things that should have slowed them down.
Now, my Macbook Pro acts like it is only maybe six months old instead of three.