From someone that has had knock off and name brand (rigid industries). I am not bashing on anyone with knockoffs, I think they have their place and I'll explain that later. First, I did not pay retail for the rigid stuff, I have gotten them on killer deals. Second a list of lights I have had. The knockoffs, all lifetimeled brand: 1 13.5" double row, 1 40.5" double row, 1 30" single row, and a pair of cubes in white. All of these were a combo beam pattern (spot and flood) other than the cubes we're a spot beam. Now to what I have currently... The rigid stuff, 1 30" single row, 1 set of white spot cubes, and 1 set Amber flood cubes.
Brightness: pretty much the same. But this is NOT what matters. Any array of 4,8,10 ECT... 5w LEDs will produce a lot of light, that is the nature of them. So I personally don't care how many "lumens" they produce. It can be handy to know this but it is not the biggest factor.
Build: rigid is better, but not by 5x the price. They are all metal housings with polycarbonate lens. I will say the rigid is a bit heavier and feels better and has an overall better appearance as far as quality is concerned. But again it is had to mess up metal and plastic lol. I will say the only bar I have ever had moisture in was the 13.5" knockoff. I had to replace it 3 times under warranty.
Actual usable light. THIS IS WHAT MATTERS! This comes down to the brightness (that we already know is good from all sides) with the addition of BEAM ANGLE. Simply put the rigid mean angle is better in every way without argument. The general Spot beam for a knockoff is 30degrees. This is measured center out (I am pretty sure... Not 100% on that) and on one bar I had it was a 20 degree spot (the lifetime single row 30"). The flood pattern for knockoffs is 60 degrees and the single row lifetimeled is 40 degrees. Now compare that to the rigid. Their standard spot has a 10 degree pattern with an optional 5 degree hyperspot (I have never used one of those). And a flood pattern of 20 degrees (optional diffused lens if you need more than 20 degrees).
So if you have two bars that produce the same lumens but one has a 30 degree "spot" and the other has a 10 degree, what do you think will have more useable light? Now what I have been talking is getting distance from your light. I'll say that my pair of rigid spot cubes shines the same distance as the lifetime 30". So now think of how far a 30" with the same optics will shine..... Of course, I do not have as much flood light from these rigid products and that is true. This is where knockoffs come in handy. If you want flood lighting, 100% go knockoff and don't look back! Heck, I have 6 $11 per pair lights around my roof rack because they work great for area lighting!
Summary: I think both cheap and name brand has their place and is worth it. I do think if someone can afford to buy the name brands, and has the use for them then I 100% recommend them. The flip side is that they are very expensive... So obviously get what you can afford. You still won't be disappointed in buying a cheap bar. Just know when to use it (I'll give you a hint, not on roads). Hope this can shed some light (hehehehe) on name brand vs cheap and what really sets them apart. Just remember, brightness hardly matters compared to beam angle.
TL;DR. Both are bright. Rigid shines far (way way way farther), knockoffs are great if you want flood lighting or just want some standard extra light.
