I have an OTC stinger light I really like. It has digital timing so no knob errors and it also has a tach in the display, so far it works with HEI, CD (MSD style) and DIS (coil near plug)ignitions and I've tested the accuracy on the balancer with marks and it is dead on every time. The only thing it doesn't work for is it has a filter that won't allow it to trigger during cranking, so the engine has to be running. I would get the same one again because it allows you to test vacuum and mechanical advance curves and you don't need the timing marks or balancer tape on the balancer.
Ok, I just looked and it doesn't appear that make that model any more, but it looks exactly like this one...
Timing Light
However, I'm not sure if that is the same or not so I can't say if it works for CD multispark ignitions.
But in general, I would say it's worth it for a "digital" advance timing light, because the digital takes the error out of the knob type units with a sticker on them. Plus the built in tach allows you to do it all from the engine compartment so you don't have to climb in and out of the cab.