Nexus 5 phone. Just got back from two weeks in China and Japan. Bought ATT 300 GB plan for 60 bucks before I left. Plenty, since I watched my high data volume use while on mobile data. Nexus makes this easy since you can check data usage by app.
Wife took her Iphone which sucked data like a sponge. Think it was status updates?
Anyway, considering the money spent on flights, lodging and food, a 1-200 bucks for data seems like small change. And it was nice knowing that if a stateside emergency arose (92 year old mother for example), I would be an easy phone call away.
Wifi is pretty common in Beijing, Shanghai and of course Tokyo, so why sweat mobile data so much?