The phone comes in immaculate packaging, as with any Apple product. I believe the iPhone 5's box is moderately smaller than that of the original iPhone's. Inside the box, you will find the iPhone 5 sitting at the top layer, underneath a packet of manuals other textual paraphernalia, and finally a 5W USB charger, Apple EarPods, and a Lightning cable.
I immediately saw two imperfections with my phone, both at the lower right on the aluminum. They're at most 0.5mm wide; I don't own a micrometer or have one handy, but they're certainly less than a millimeter in width. That said, I will not be exchanging the phone or putting it in a case.
When you pick up the phone, you notice how thin and light it is. 0.8oz is nothing impressive on paper, but it is very tangible in your hand. In addition, the thinness of the phone is tangible as well, but not as much as the lack of weight.
The phone boots very quickly in about 7-10s. You are then greeted by the setup assistant, which works just like the one in iOS 5. I restored my phone using my iPad 2's backup on iCloud, which took no more than two minutes.
Moving around in iOS 6 is very zippy. I haven't yet felt any lag navigating around or while using apps. Gaming is butter smooth as well; Real Racing 2 flies, although extremely cramped on a phone compared to on iPad. The phone stays cool while gaming.
I have noticed one glitch, probably caused by video drivers, but it might be hardware related. The screen will display about 5 rows of scrambled lines when I switch between the numbers keyboard and the qwerty keyboard while typing my password for the App Stores. This bug is pretty hard to reproduce; it's only happened three times to me so far.
I also noticed that the phone gets quite warm while browsing on LTE. The aluminum especially acts like a fantastic hand warmer (will definitely be useful for the upcoming Boston winter).
Battery life has been great as well. I got a bit more than 10 hours of use surfing the web, playing some light games, and listening to 5 hours of music on and off. Push Exchange was on the entire time. I predict that I will have to charge the phone every 1.5 days, compared to every night with my previous phones (iPhone, Dell Streak, HTC HD2).
The included EarPods are decent. They have more bass than Apple's in ears, but cannot touch my B&W P5's or my Sennheiser HD428s. The treble and midtones are not as warm as the P5's. Unfortunately, without any removable grill design, they look like they will be jammed by earwax by some point in the future. That said, they're definitely a step up from the previously included earbuds.
Lightning works well. The cable is indeed bidirectional and it's also very small. I'm not bothered by the lack of compatibility with old accessories because, well, I don't have or use any besides the cables.