At 120 hours, the light might still be producing light, but it would be useful at all. It has no regulation(which means it dims as the battery died) and Coast has a different definition of runtime(probably until the LED won't light up).
What were the other LED lights? If they used 5MM LEDs, of course they won't match up. I'd be willing to bet that
this light is brighter then your Coast though(but is is larger too, and requires different batteries, though you can buy the whole set with batteries and charger for under $50 shipped).