Well, as bellarinelawns says, it'd need to be in near showroom condition to be worth $200!
Rarity doesn't usually translate to valuable, in OPE collecting. Except for the few machines that become sought after by 'cult followers' - the Victa Model 4 Automatic mower is the prime example of that.
Whirlwind wasn't unknown for incorporating other manufacturers' features in their machines, but who knows if they or SB was the copier, or if they both copied from elsewhere!
With a really simple machine like an edger, the points to look at are firstly engine age and condition, then the design and condition of the cut depth adjustment, and that all guarding is fitted and functional. And maybe the condition of the wheels, as some edgers have up to 6 of them. Belts and blades are easily replaced, so not of great concern.
My personal preference is a machine where the blade rotation 'pulls' the machine along, and for a disc blade as used on Rover and some Victa TaC models.
