Based on recommendations from correspondents, and on WWW research, I purchased a Planet Bike Superflash taillight at REI yesterday.
It's $25 pretty much everywhere... I took advantage of the 20% off member discount currently going on, so I got it for $20 plus tax.
If they'd had the "stealth" model (clear lens instead of red), I would've gotten that one. The LEDs are red, anyway, and the clear lens probably transmits more light. But red is all they had.
It is amazingly bright and the jittery flash pattern is attention-getting. (The first time I turned it on, I was looking directly at it... saw spots for a few minutes afterwards.) I doubt that anyone has been rear-ended while using the Superflash.
My intended use is for day-to-day riding when visibility is compromised - night, and early or late in the day. Or when I happen not to be wearing the hi-viz vest... which isn't often any more. (I'll post more about my vest exerience soon.) When I depart on a night ride, I'll supplement it with the Lightman xenon strobe.
It came in useful the first night. I went and watched the football game at my mom's place, and rode home in the dark and the rain afterwards. I was sporting my hi-viz jacket and hi-viz/reflector vest, the Strobe, plus the Superflash. Motorists gave me a wide berth. Very comforting to feel confident that I was being seen!!
(OFF-TOPIC: I was dripping wet - from the waist down - when I got home, but the jacket seemed to effectively shed water. Rain, and being wet, is overrated as a misery-inducer, in our comfort obsessed society. It would be one thing if you were wet for days or weeks at a time, like jungle-fighting during monsoon season. Or when combined with uncomfortable cold... but otherwise, you get wet, and you get dry. I deliberately got myself wet, earlier the same day! grin)
I will do some real-life comparison (my opinion, of course) between the Superflash and the Strobe sometime soon. Maybe throw in whatever taillight the replacement bike arrives with... golly, I hope I don't have to wait much longer!