I have both and the first thing that comes to mind is the size difference. The X0 is large compared to the X1 or the X5. The X1 is a good light, but I only used it in area that are already partically lit. I use it to see behind computers or backs of switches at my job. The X0 is very bright and has a very good throw. I would use it outside or in much darker areas, although I wouldn't use it for a walking light becuase there is not much spill to it. Hope that helps a little.