That said, I am uncertain about whether to change providers and go to SoftBank in order to get one.
Changing providers doesn't bother me so much. And with number portability I would be able to keep the same number.
What I am uncertain about is the balance between the features I would lose vs what I would gain with the iPhone.
To be sure, the browser on the iPhone is the best mobile browser by far. It definitely beats any mobile browser on any other cell phone here. And having the iPod features is nice.
But there are things that the existing cell phones here do, which are very useful, that I am not sure I want to give up. For example:
(1) My cell phone has a built in chip that lets me use the phone for all sorts of daily payments. I can use it to get on the train, subway and buses. I can use it to buy stuff at convenience stores and a lot of other places too, including vending machines. It would be a nuisance to not be able to do that any more.
(2) The cell phone camera I currently have is much better than the one in the iPhone. It has higher resolution, auto-focus and it takes videos, which I like doing.
(3) MY cell phone has built-in "one-seg", which is a digital TV broadcast receiver. I don't watch TV much on my cell phone, but it's nice to have when you need it.
I could live without (3). But (1) and (2) would actually be giving up important features that I use all the time.
Plus I really like having a keyboard - though I suspect composing English messages will be easier on the iPhone than it is on the Japanese cell phone keypads. Composing Japanese messages right now is pretty quick and easy. But the phones here are really not designed for composing English messages, and they are actually harder to type in than Japanese messages right now. That would be a plus for the iPhone.
I think I might at least have to wait until the iPhone at least supports the payment chip and a better camera before I make the leap.
And if there is a two year minimum contract required, the thing better be guaranteed for two years!