I have one of these lasers on an old 10" chop saw and do not like it at all. The red line is wider than a pencil line, creates such a bright light that has so high a contrast to the surrounding piece that it makes it difficult to see any pencil marks (knife, chaulk, etc.) on the piece being cut, is nearly impossible to adjust perfectly in line with the edge of the cut, and requires one on both sides of the blade if you ever intend to alternate between which side is the "keep" side.
A better (and cheaper) option is simply more light. You can buy a daylight spectrum fluorescent flood light plus a clamping reflector (~$10 at HD) if you want to put light directly on the cutting zone. Better would be two (~$20), one for each side of the blade to eliminate shadows. Another cheap option is a 4' two-bulb T8 fixture (~$15 at Walmart) suspended directly over the work area.
It is surprising how much increasing footcandles helps you to see fine detail. My Architectural Graphics Standards recommends a minimum 200 footcandles in "Factory, difficult assembly areas" all the way up to 1,000 footcandles for "Factory, exacting assembly". I would say that woodworking, especially using dangerous saws to cut to <1/64" accuracy qualifies more toward the latter. But I bet very few of us have even 20!
I just got the new Milwaukee sliding miter two days ago and it has a built-in light on either side of the blade. Wow, does that help to cut right on the line! Not only can I see the blade but I can see its exact relationship to the cut line mark. I've also recently exchanged some of my old incandescent fixtures for daylight spectrum fluorescents and the increased brightness really helps me be more accurate.
I can't recommend brighter lighting enough, for the same price as the saw laser you could probably add area lighting at the saw station and one or two others.
