I use the step to wash the window, so that's out as a mounting location for me.
The LEDs themselves are exactly the same, it's the housing that differs between the cheap lights and the expensive ones. Maybe the lenses; glass would be much more durable than plastic over the years. And there are different styles of lens shape, to; projector, flood, refracting, etc. If someone is going to bash about on back roads a lot, then by all means get the sturdiest product you can afford. For the 98% of us who drive on pavement and maintained gravel/dirt roads 99% of the time, the cheaper lights should be perfectly fine.
Looking at the ads, I was wondering about how they quantify their products. I know Lumens are a measurement of brightness, and that watts are a measure of power consumption. Many of these lights list "watts" to describe how powerful the lights are, which is erroneous when comparing LED to HID or standard bulbs. For an LED light system to use 500 watts, it must be pretty **** bright. many of the light bars are made with 3-5 watt individual LEDs, so a 500 watt system would use 200-300 individual LEDs. My 1200 lumen flashlight is pretty **** bright, so I can just imagine what these 50,000 lumen light bars can do!
Regular car headlights are 800-1500 lumens depending on brand and type. HID headlights are up to 3500 lumens.
Quantifying brightness; 1 candlepower = 12.57 Lumens. Remember the old 15 million candlepower spotlights? That would be 188 million Lumens! I think the way they measured and rated those spotlights was off...a bit! Lux is 1 lumen to 1 square meter, another measurement of note.
A lot of products are measured at 3 meters, or about 10'. Depending on quality and efficiency of the lens material, a light that measures 1000 lumens at 3 meters may be much brighter at 100 meters than a light that measures 5000 lumens at 3 meters. It's best to do a little research and read reviews to see if something is actually going to do what you want it to do.