I am a softbank user for the past 7 years. The only problem I had with them was when they started with iphone and somewhere their system got screwed. My cousin sent me a picture from her iphone to my normal phone and that image kept coming back till my bill went up to 30,000yen.
When I called the Softbank support center and even went to their office , their Services SUCKS!! nobody know shit.. My cousins husband call their office directly and was able to get hold of someone who knows what they were talking about and not reading from some manuals. Fortunately, all the bills were erased and I was charged with my normal bills which is around 3K.
But i stayed with softbank not because I like them but because its too troublesome to change numbers and I still prefer the SMS service over email. I don't surf the net with my fone or take picture with it .. so I am paying only the very basic.
So unless u really have too, don't get softbank.
Right now, AU has the widest coverage all over Japan. Then next is Docomo.
If you use your phone mostly for business purposes, I think Docomo is your best choice.
When it comes to customer support and services I think Docomo and AU are on the same level.
If you ever go with softbank because of Iphone or Ipad, be sure to read the billing details in their english website. Everything is there except they are written in really small letters
