Our family of 4 (with two toddlers) just got back from vacation in Japan and we had GranClass seats on the Hakutaka train from Tokyo to Kanazawa. We got 3 seats (2 adult and 1 child fare) and it came out to $435 USD. I think the Green class fare was about $100 less and the standard fare was about $200 less. But for a 3 hour ride with kids the premium was definitely worth it.

We didn't have food service on the train, but we just bought bento boxes and drinks at the station before boarding. The GranClass cabin and seats are beautiful. Although the seats aren't fully lie flat, the fit and finish of everything inside the car are on par with a QSuite.

I would 100% recommend it if you are looking for a comfortable ride on a long route like ours.