I'd say that it's no better or worse than places in town like Teapot. Most of the food was fresh and decent (the sushi chef made us rolls to order when there were no cuke only for my kids), but not excellent. It was a fun place to take the kids, and since I live around the corner I might go back once in a while for their benefit. (Really, I can have 3 bowls of miso soup???)
I have a weakness for Chinese buffets, and I have been to some REALLY bad ones, Brattleboro Vt, and Greenfield Ma come to mind. Sakura is above average for a buffet, but not in the same league as a the good chinese restaurants in the area such as Ahmerst Chinese, Butterfly, or Great Wall. They charge around $10 weekdays, I don't know what it costs weeknights.
1168 Boston Rd, Springfield, MA 01119
I guess this restaurant's not in Chowhound yet?
Anyway, I went here last Sunday at around 1pm. There we not many people in the establishment, my party and maybe 4 or 5 others. It was $20/ person. All I heard was that it was a sushi buffet, so I was quite surprised to see Cantonese style lobster. I will say me and my party immediately flocked to that tray. At first the lobster was undercooked. We mentioned this to the waitress and she checked with the chef, came back and basically said they apologize and they have new lobster out that is cooked. I was very surprised to get such professional service at a buffet. Anyway, the new lobster was excellent. I also had my fair share of Sushi which was very good for a buffet. They make most of the sushi in small batches, so it doesn't sit for too long. The rolls were good, the nigiri a little light on the fish, but it's to be expected from a buffet. The Sushi wasn't as good as Osaka or anything, but considering it was a buffet, no complaints. The hot dishes were pretty good (surprisingly good tempura) and they had a few interesting dishes like grilled head-on shrimp on a skewer. The raw oysters and Clams were terrible, although I was not expecting much. All in all though, I was pleasantly surprised. I agree with you and I don't see them lasting to long as there weren't many people there, so you might as well try them when you get a chance.