Build quality is fine, but not elegant by any stretch. There's not much to it. It's a square metal box with vents on the side and back. The reflector seems pretty shiny and there is a glass protector over the opening-- looks kind of like a big flashlight.
Inside, the LED is screwed to a "sunflower" heatsink with some thermal paste, so I could easily pull the chip off if I wanted. There's a fan on the other side of the heatsink that blows air out of the top of the box. It's not a quiet fan, but inside the cabinet, it will be fine.
There's a plug, a switch, a 12v power supply for the fan, and a 600mA 55-70V driver for the LEDs.
Note that makes it at most a 42W light, not 75W. The advertised "75W" is because there are 25 "3W" LEDs. However, typical red "3W" LEDs only take 2.5V or so, and driven at 600mA, they actually consume only 1.5W. In the advert it says the light "consumes" 45W.
All of the components could be switched out very easily.
I think this light will be fine for growing cheato, but certainly won't be burning it with too much par. I probably could have gone with their "200W" version (which "consumes" 110W). Even at 45W or so, it's still less expensive than what I would have done DIY for the same power output. The build quality and fit of the components is fine. Plus, I didn't have to spend three or four hours putting it together.
Edit: I have it sitting on a piece of glass spanning the edges of the sump, so 8-10" off the water. View angle of the reflector is roughly 90 degrees, so the light pretty much covers the 17x17" area without too much spillage outside of it.