The SR80 provides nearly twice the light at little more than half of
the cost of the IQ Speed + battery package.
Here's the Blog site: http://blog.dutchbikebits.com/2011/12/top-quality-bicycle-lights-for-roads.html?m=1
I also ordered the Philips LumiRing Rear Light.
Very cool new design.
Happy Trails!
Michael D.