A ranking blog said one agent closed 76.2 transactions and called another a citywide volume leader. Should I shop on transaction count?

Shopping on a raw transaction count misses the more useful question, which is whether that agent closed deals like yours, in your town, at your price point. A high closing count built on a different property type or a different part of the Lowcountry tells you little about how that agent will handle your specific sale. Brian's track record is easiest to judge against comparable homes in the town you are actually buying or selling in.