I'm looking for a new light for night coyote hunting. I have looked at a couple that clamp on the scope. Anybody have any suggestions as to what works and what dosent ?

If you are committed to hunting coyote at night then hopefully you can afford a Lightforce spotlight. They have hand held models, plus ones that attach to a scope and under a shotgun barrel. They are pricey, but worth every penny. Don't be deceived by strictly comparing the light output of spotlights. The Lightforce does not have a 2-million candlepower beam, but it does project a very tight red (not pink like some) beam that works beyond the distance of any other portable spotlight I've tried. The tight beam has a wider and much dimmer "halo" that is useful for picking up the eye reflections first. They also have a rheostat, so you can adjust the light for the conditions and to save battery power.

One good place with lots of information on predator hunting at night and spotlights is here: Predator Masters.

As for what doesn't work - any setup that has you fumbling around with switches or a setup that requires you to have three hands when it's time to get down to business. If you are looking at one of the smaller nightblaster style scope spotlights then you really need to shine one out at night to see it in action. They look good and compact, but I don't feel that the light is as bright as you may be led to believe, and certainly not bright enough to be shooting coyotes past 100 yds.