I don't personally think that a blinking LED vest is much more visible than a good normal reflective vest. In fact I kind of doubt that the LEDs would be visible in the glare from the reflective tape, if the tape is good stuff. The LEDs are probably most useful if you're not in the headlight beam, but if that's the case I'm not sure you're actually in danger anyway.

For sure let us know, but I'd like to see pics/video from a moving car of a reflective vest and the LED vest.