It says it has a "momentary on switch". That sounds to me like you have to hold it, which is fine if you're using it around the house, but slightly harder if you're on a bike.

I think the two I'm looking at now are the Ultrafire C3 and WF-606A. This thread is a bit old, but it seems as though the WF-606A is a bit brighter. But the C3 has modes !! The reviews on deal extreme (I'll probably order elsewhere, but they have 40 something reviews on each) seem to favor the C3 for biking, and it got 10x more diggs, but that could have been some nut clicking it a lot. Oh, decisions! It seems like the WF-606 is brighter and smoother spread, but it's hard to tell from pictures.