So...I used to use Zagat quite a bit, and found that restaurants in the 28+ food category were consistently great, and 27 was usually good if not necessarily top tier.
Then, they made some sort of horrible switch to a blog format post Google takeover. Zagat became completely unusable.
Recently, they responded to the feedback and allowed users to sort by food score, etc. which makes the rating system useful again.
I noticed some changes, such as Zahav moving from a 29 (seemed high to me back in the day) to 27 (seems a point low).
Anyway, I used it to guide me to Fond (fantastic!) which was a 28 over Dandelion, whose 23 food score worried me (that's insanely low), but the high decor of Dandelion made sense. ;)