I'm not sure how Sushi Box compares to the other Japanese venues in Waltham, but we found it to be about average compared to other sushi restaurants we've been to. Everything was fresh, prices very reasonable, service was good, but none of the sushi or maki wowed us in any way. I would consider returning to try some of the non sushi items as there is Korean and Thai choices as well.
The hostess and waitress was super friendly and checked in on us frequently to see if we were happy or needed anything else.
Note: There is no alcohol served, soft drinks and tea only.