4 stars. I've been to Yamamoto many times including à la carte & AYCE lunch and the AYCE dinner. For the best value for food, I would come here for the à la carte lunch. The bentos are reasonably priced with decent portions and quality. The price for the AYCE is definitely competitive with other places.
The most positive thing about this restaurant is that they don't (or rarely) mess up orders. I have been to too many places where they do and it's a struggle to even get the food you ordered.
Most items come promptly even when the place is packed. There is a good number of waiters around so you can usually catch one of their attention quickly. The sushi and especially the tempura comes late often but they take longer to make/prepare.
I have not tried the fish you have to pay extra for on the special menu.
I think their tempura is below average (it's not dry enough) so take caution in ordering a lot. The sushi is above average quality in comparison with other AYCE restaurants so that is a huge plus. The kalbi is much better than the sirloin steak every time I tried them. I actually like how small most of the portions were (specifically the noodles). You can try a variety of food without getting too full. The variety of food isn't the greatest but it is good enough that you won't feel ripped off. The selection of desserts is loved by many. They come in a small glass, so again, you can try a variety without getting full.
What brings the rating down for me is the overall quality of food. Compared to other Japanese AYCE, this place is fantastic! But it's only so because the competition is so lacking. While I do love the food here, I can only find myself going back maybe once a month.
Overall a reliable pick for a dinner out. Make sure you book a table on weekends as it can get full.