Thank you for your investigation and input Burton and yours as well no1mad.
I too have viewed the videos on the Serfas site and compared the 200 and 60. Using the video time bar at bottom of video it seemed to me that the 60 was more visible for a few seconds longer than the 200. But that may be my imagination, cause when you compare most of the tail light videos, even the ones designed for seat stay (Thunderbolt) which is a long narrow light they all look like the same light when the car passes to me...
At any rate I should have one here in a couple days. Hope it is worth it. The Cygolite Hot Shot looks pretty good as well plus it is less expensive. I might just "have" to get one of those as well and do a comparison myself