I quote pi.ai:
Both Panamax and Furman are owned by the same parent company, Linear, LLC, which is a division of Nortek, Inc. In 2006, Panamax acquired Furman Sound, and since then, Furman has operated as a second brand within Panamax.
When I last looked, some Panamax high end surge protectors included the Furman features of SMP and LiFT.
You are right that a lot of snake oil in this business exists which is why I always turn to the Wirecutter article which is, as far as I know, the only third-party survey of surge protectors which actually includes 5kV surge testing.
The Furman brand has long been associated with professional sound gear as well as home gear.