When Google rolled out G+ Local with Zagat reviews they changed the ordering of review content from time based to most helpful. As part of that ordering they added a new category of reviewer known as a Top Reviewers. These were folks that had reviewed a large number of locations. Google also added the ability for a business (and I presume its many managers) to leave reviews of other businesses.
Like all things Google the Most Helpful ordering of reviews is algo based and includes elements like the quality of the reviewer (in terms of followers on G+ and number of reviews), the language of the review, the recency of the review and who knows what else. One of the attributes of reviewer quality is the Top Reviewer assignation. According to this post to become a Top Reviewer one needs lots of reviews, a significant number of followers and a reviews that have been found helpful by others. It is not clear whether being reviewed by a Top Reviewer increases rank but there is every reason to assume that a review from a Top Reviewer is carefully watched by Google for other signals and content.
What never occurred to me until this morning was that one way to become a Top Reviewer was to do so as a Google+ Page for your business rather than an individual. A business page can have as many as 50 managers so reviews would aggregate more quickly and ease the burden of any individual reviewer. Obviously this business recognized the opportunity and has leveraged it.How to Get Review Cred in G+ Local as a Top Reviewer- As a Business Page by Mike Blumenthal