I'm a little over 24 hours in so I thought I'd share my thoughts. I upgraded from the 4S to the 5, both phones on AT&T.
* LTE is wicked fast. Multiple speed tests show it well exceeds the "4G" (HSPA +), almost as fast as my wi-fi. Speeds here in Tampa Bay aren't what they are in other cities, but better than what I had before.
* The weight of the 5 is very surprising. Apple put this thing on a crash diet, and it worked. The handset feels solid and well-built, but it is feather light.
* The 4S had a great display, but the 5's is better. Not drastically so, but enough to notice & make a difference. Impressed.
* Overall speed of the phone (launching apps, Safari page loads, etc.) is wicked.
* The ear pods are a HUGE improvement over the old ear buds.
* I have the black & slate, and my phone (thankfully, luckily) came to me in pristine shape. No imperfections on the finish anywhere. The slate anodized aluminum takes on almost a bluish hue in certain light, which looks awesome. I had a white 4S which I loved, but I like the stealth black & matte slate as much if not more.
* Battery life is great so far. I had zero problems with my 4S and so far the battery on the 5 is the same. I plan to do at least one full discharge/recharge cycle but thus far I'm totally satisfied.
* Size: I really like the extra screen space and the stretched chassis & display. I definitely prefer it to the 4S. I wouldn't mind seeing Apple increase the width by 0.5", but as is I prefer the 5's dimensions to the oversized Android handsets.
I paid extra for an early upgrade and am selling my 4S to help cover the difference, but I'm totally satisfied with the iPhone 5. Despite the many lukewarm responses to the reveal and early reviews, I'm very happy. This is not just a "stretched 4S". Those who say that haven't experienced the 5 in person. Not thoroughly overwhelmed as I was during the upgrade from 3GS to 4S - that was a bigger jump in EVERY single way - but to me the 5 was well worth the time & money. Huge value for the money here, and to the naysayers, all I can say is "haters gonna hate", so go on with your bad selves.