I have 2 of the red Nite Ize lights on each wheel. I haven't had the batteries die on me yet, but I've only been using them for a couple months.
I agree that it would be even better to see a brighter version of them on the market.

I will say, though, that they seem to get people's attention. Mostly I hear pedestrians harassing me (because it's something out of the ordinary),
but I've had times when cars stopped pulling out in front of me, where they otherwise wouldn't have before I had the spoke lights.