The iPhone has the biggest, clearest, best screen yet seen on a mobile device. Which is a lot like saying it's the world's tallest midget. We've gone from screens the size of four postage stamps, to screens the size of six postage stamps. Ninja, plz... To paraphrase HHGTTG: "Ten out of ten for excellent engineering; minus several million for common sense."
Get back to me when we have gargoyle-tech wearable displays (you WON'T look like a Borg drone!) so my screen is a reasonable size. Say 15" diagonal viewable minimum. Or maybe they could just get direct neural input working (you insensitive clods!), and sidestep all this clumsy crap. In the meantime, those who truly need a real mobile PC should look at a Samsung Q1 series UMP.
Shiny though it is, I wouldn't recommend the iPhone. Unless you're just a huge, slobbering Apple fanboy. In which case the iPhone is perfect for you!