The slight increase in size makes iPhone better for both reading and watching. The reduced girth makes it fit better in your pocket. The lighter weight make you less anxious that a small-but-heavy objet-d’art will slip from your butterfingers. And the beefier battery — still almost full this morning after a charge yesterday around noon — makes you just a little less soup Nazi about ensuring your phone is fully charged before leaving the house in the morning.
One caution about the pocket thing?
Be careful about bending over to tie your shoes with iPhone 5 in your front pocket. That one extra row of icons could completely mitigate iPhone 5′s inexplicable inability to induce amatory attitudes in your significant other.
I’m not really concerned about the aluminum-is-a-softer-metal scratch factor. Phones are tools, tools get used, and used things take wear. It’s a fact of life that I’m resigned to, and since I’m rabidly anti-case (anti anything that adds weight and bulk to my devices, actually), it’s something that I’ve learned to live with.
Besides, I picked white, which has fewer issues by all accounts than black....

