Which iPhone 6 should I bring? From USA

I have tried doing research on which iPhone 6 or 6 plus is the most compatible for all the best features in Japan. Verizon is what I came up with.

Do you guys think any different? From experience?
There is AT&T, T-Mobile, Sprint, or Verizon.

Thanks!

I recommend T Mobile! I used my Note 4 in Japan last month, and my T Mobile plan worked perfectly. Data was a bit on the slow side, and I had to be on a WiFi network to make calls, but I didn't need pocket WiFi or a different Sim card.

Are you talking about for travelling in Japan and using your US plan? In that case t-mobile is probably the most affordable as they offer plans with limited, free international data. If you are talking about moving and using a Japanese provider, then all models will basically work the same provided they are unlocked.

btw, what are the specific features that are you interested in using in Japan?

I plan to use it with b mobile or other prepaid sim services in Japan for calling, texting and data. Should i bring one from home or would an iPhone bought from Japan be better, in ways?

I plan to use it with b mobile or other prepaid sim services in Japan for calling, texting and data.

Living or travelling? Note that some of b-mobiles plans are not utilizing the fastest networks, so you won't be getting all you can out of your phone.

Should i bring one from home or would an iPhone bought from Japan be better, in ways?

They would be the same provided they are unlocked.