i have asked this same ? and I would say that the lumen brights are better but the price is about 4 times the spider reflectors and that was the deciding factor for me and I really like them I got the larger ones that are 16x13x5 and am running 3 of them with 250Ws each.
Here is a link to the ones that I got.
Sure there have been tests done, but could not send you to any links.
The basic design of the Lumenbrite makes it a better reflector. ALL of the light is focused down into the tank, whereas with the spiders only part of it is. You lose light on both ends.
The application of the reflector also has to be taken into consideration.The only type I could squeeze into my 90's canopy, along with VHO's, were spiders. And even that is not ideal. I had to mount the VHO's so they sit inside the spiders, cutting down on their ability to reflect light into the tank. But with the inside of the canopy painted white, it seems as if enough light still makes it into the tank.
Are they three times better? I don't know. But the next tank I set up will not have a canopy, and I'll definitely use a Lumenbrite or similar reflector.
Ya. Those are very nice. I looked at them too, but the design of my canopy won't allow for it. I really don't have enough distance from the top of the canopy to the canopy doors, because I would want to build standoffs for the VHOs to get them at least level with the bottom of the MH reflectors. So the VHOs would be in the way.
I personally do not think you need to spend the extra cash if the inside of the canopy is painted white. The enclosed design forces all the light to the tank. Someone I know lined the inside of his canopy with 1/8" white acrylic. Extremely nice. Major light reflection, and a breeze to wipe off any salt spray. Though I would imagine if you figure in the cost of the acrylic, you would probably be pretty close to the price of the nicer reflectors. lol