Negitoro don vs toro sushi
Is the toro in negitoro don the same quality as what you'd find for toro sushi (nigiri)? Is it even toro, or just regular tuna (maguro)? I imagine it's at least a lower quality.
Technically it shouldn't be, but all the places I have been to (e.g., Japanese grocery stores or Maru Ichi in Mountain View) almost always offer not-very-fatty tuna in their negitoro don. One advantage of serving negitoro is that a chef doesn't have to trim the tuna to make it into a pretty piece for nigiri (and remove the outside parts that are equally good in taste). In other words, if you go to a reputable sushi house, a negitoro don should still be very good (and not cheap). That's why it's more common to see a negitoro maki (roll) with much less tuna instead of a full don (rice bowl).