A Best gun is a fickle topic at best.
I was just looking at a Browning 20 ga. BSS sidelock. It has many of the accruements that are accounted as being in the Best category but not the name. Should the same gun have been built by Purdey, Boss, Woodward, etc. I expect it would find more favour along side the Best's.
I own a McNaughton Edinburgh that is considered one of the most elegant and sexy guns alive with its trigger plated skeleton stocked action. I don't find it that way, however. The checkering is English flat top at 18 lines per inch and doesn't match the engraving or styling of the gun. The forend is plain and snap on. Rather crude for a gun of stature. It does have exciting wood, fine damascus barrels, top lever cocking with indicators and is the best balanced handling gun I own.
I also own a Scott sidelock back action, with crystal indicators and top lever cocking. It was finished by Sumners of Liverpool. It screams best in every category of a gun of its time. Very fine damascus barrels, engraving that equals the best, splendid wood, Scott forend release, superb fit and finish and handles on par with the McNaughton. It cost me a mere pittance. Unfortunately bastardized in its restoration.
So when it is said here that a Best is a marketing ploy, in large part I am inclined to agree.
