We often get asked why LED's are 'better' than incandescent bulbs/lamps and now the technology is getting to a point where it easily surpasses the older tech in certain applications its worth pointing a couple of things out.
1: They use far less power and are more efficient i.e they put out more lumens per watt. This is good as they are generally much much brighter, are ideal for rapid on/off applications and can be used normally on vehicles when the engine is off. Even the biggest LED light flashing light bars only draw a few amps so its safe to leave them running for extended periods without flattening your battery.
2: They are more expensive. Arguably the biggest deal breaker but bear in mind an entire light bar is usually filled with modules where older style rotators only had units at the end and maybe one in the middle. You're also getting a 3-5 year warranty with LED bars now too. Normal LED's found in things like marker lights can vary in price too. One of the factors in this is popularity. Amber side markers are sold more so it stands to reason that they are cheaper. White and blue LEDs are almost always dearer but theres an extra step or two involved making the diode wafer itself so it could be down to that too. Be wary of cheap imitations, you could be dealing with inferior diodes with off colour tones, rapid dulling and B grade modules with no warranties. Quite often lenses are made from acrylic based materials rather than polycarbonate and can cloud up due to the suns UV's damaging the acrylic structure.
For the full run down on LED technology I've found this Wiki page very informative: link
Ok, so when people are looking at LED lights, worklights in particular, the usual piece of information used to gauge the brightness is the lumen rating. The best way to put this into perspective is to say that 1600 lumens is the same as the brightness of a 100W incandecent bulb. This is supposedly equivalant to a total LED wattage combined of 18-22W. However when you understand the following statement about lumens it starts to get a bit dodgy:
"The lumen can be thought of casually as a measure of the total "amount" of visible light in some defined beam or angle, or emitted from some source. The number of candelas or lumens from a source also depends on its spectrum, via the nominal response of the human eye as represented in the luminosity function."
In otherwords these 1600 Lumens could be measured over an area the size of your living room or a football pitch and give very different readings. Its also worth questioning at what angle and distance it measured at. The fact is it isn't measured at all. Its a theoretical measurement based on the percieved total output combined with the wattage. Hmmmmm....
In reality we have lit two different lights with the same lumens rating and found them to be different in percieved brightness due to beam pattern, position/pattern of LEDs in the lamps, recessed into a mirrored cavity or surface mounted, colour temperature (Kelvin), ambient light combined with Kelvin and so on and so on. Its surprised us from time to time and usuallly its beam pattern that really throws you the most.
So the best advice we can give is to see for yourself. The Hella lamps we have on the site have a link to Hella virtual showcase to see the diferences as they would appear on a dark road. This is a handy tool for seeing how these different types of lights can compare generally but there's really no substitute for seeing for yourself. We make a point of trying out the lamps as the appear in stock, typically in winter, and try them out with the lights off or even out the back. It really is the best way for us to gauge what each light is most suited to in terms of vehicle or application. If you're local to us please feel free to pop in to test some out or if you're further field you could purchase a small selection of work lights to try hooked to a power source and see that way. As long as the returned items are in the same condition they were sold in initially you'll receive a full refund. With LED light bars and flashers they're all insanely bright and the more recent ones are probably on the cusp of being too bright. No need to test those unless you're mental and enjoy stumbling about your back garden clutching your eyes because you looked right in one at arms length.
Check out this link to Wikipedia's article on Lumens: link