Well, in our use at the water plant, the light just stays in one place so I can't really speak much about moving it around. It doesn't seem very heavy. It is the the metal halide version but it is the yellow case, not black as pictured on the website. I would say the 40-56 ft diameter work area is about right, maybe even a little conservative. I would say that would be for "bright" illumination, easily 2-3 times that distance for just general illumination. The only disadvantages I've noticed are really slow startup and, depending on your uses, noise from the fan that keeps it cool. The startup isn't like with a HID spotlight. After you turn it on, for the first 15 seconds or so, you think the light is broken because there is no light, just the sound of the fan. Then it starts to glow a little, kind of like a burnt out fluorescent bulb sometimes does at the end of the tube. And then it slowly ramps up to full brightness over several minutes. I've never timed it, since I'm doing other things at the time, but I would guess it's about 5 minutes in total. It's definitely not suited for when you need to light up an area quickly. But if you can take the wait, the light output is very impressive. The fan sound is not really loud, but it is a noticable low humm. Kind of like being right next to a computer fan but audible a couple feet away. As for stepping up to 400W, I can't imagine needing more than the 250W unless your trying to light up a very large yard or a huge open building. The 250W would easily light up our shop building which is 30 by 40 ft.
