You know, I’m surprised people back the Diode light bars when it appears (on paper) that their output is SIGNIFICANTLY less than the offerings from Baja, Rigid, etc… I saw a pic of an 18” bar in the upper grill and thought is looked pretty awesome, but the Baja bar puts out 4 times the lumens!
One thing you want to remember with advertised Lumen output numbers is that most of them are total BS. The reason is that almost everyone quotes what are in effect "theoretical maximum" numbers. That means they take the maximum output from a perfect chip in perfect conditions and multiply it by the number of chips (diodes) in a product. In the real world that most of us live in, "perfect" rarely happens.
The other thing one needs to look at is how those Lumens are put to work. A given product may legitimately have a pretty decent output as measured in Lumens, but the optics suck and the light is simply blown all over the place as opposed to where you need / want it.
As for Rigid products, remember, they're significantly more expensive that everyone else due to generally superior engineering, design and manufacturing practices. You do get what you pay for.
Ah yes, the old lumens count. As Too Stroked points out, raw lumens are just a theoretical, best-case measurement of the total light leaving a source. How that light is controlled and optimized is the result of the optics in use. Consider that a highly engineered light bar, with great optics and thermal management, has a raw rating of 10,000 lumens. If you take everything else away, remove the optics and heatsinking, so that all you're left with is naked chips on a board- you still have 10,000 lumens.
Diode has chosen total infernal reflection optics (cast polycarbonate) which loses a bit of intensity due to filtering light through a thick, solid medium. However, it has a ton of efficiency because nearly all of the light coming out of each chip is carefully reflected off of a controlled, angled surface. So even if they don't have the highest lumen count, nearly all of those lumens are directed into a specific pattern (instead of being lost to glare). This is why they make excellent candidates for street legal patterns like SAE J583 fog lights and J581 auxiliary high beams. These standards have specific pattern and intensity requirements to comply to.
Baja Designs controls their lights using very deep reflectors and forward facing diodes. This has less internal losses but more "spilled light" which can be desirable for off-road use cases. This is why they do not make great candidates for street legal lighting, and they do not advertise as such (except for their SAE squadron fog, which is nerfed to the point of being dimmer than factory halogens).
KC HiLites has huge reflectors and rear-facing diodes in their gravity series. This is how they make excellently controlled lighting with huge intensities, despite using only 20 watts of power for each 6 inch lamp. They have SAE J581 driving lights too.
Most Chineseum lights you can buy will have lots of chips and a high lumen count as well. But often they have dirt-cheap shallow reflectors or lenses, which don't control the light well at all. They work okay as near range floodlights, but compare them side by side with a reputable company's lights and you'll see the difference right away.
Here's a video by Diode explaining lumens, lux, and candela.
Lumens, Lux, and Candela EXPLAINED | Diode Dynamics - YouTube
Famously, Baja Designs will tell you that lumens aren't everything too. I've been pestering them to publish more information, and they did respond (about a year ago) that they're working on more thorough spec sheets with candela, etc. So far nothing yet. They tend to do things their way, which is by making podium in many off-road races.