As far as quality issues, there are few. Litho addressed all of them, really. You need a glass lens, 3D body and metal reflector. All of those are pretty straightforward and I'm not aware of a huge difference, although Fivemega's reflectors are the standard. The real differences are in the bulbs (potting these bulbs can be tricky, and they're expensive, so you want to get them from someone who knows what they're doing) and the carrier. For average intermittant use, like mine, the plastic carriers have worked fine if you're careful with them. They have to be made very thin and you can break the plastic tabs if you're not careful. Fivemega's carrier is a thing of beauty, you can charge through it, and if you're going to be using the light a lot, go for it. If you're just going to occasionally take it out to blind somebody, the plastic ones work fine.