This is a quality product, very pleased with the Craftsmanship & functionality of this light. The features & extra spill are what sets this light apart from others. I had to play with it a little as the directions & actual functions didn't quite match up but not a big deal. It's a light, not rocket science :). The brightness is great, this is my go to light of I want to light up EVERYTHING! the beam is certainly good but the 4000 lumens comes from a couple levels of "spill". You will certainly see everything in front of you, not just some small beam or "hotspot". This sucker is gonna light up everything far & wide, low & high. For that reason, this light is perfect for when you need to see more than just a small area. The beam is still good though & you get a good deal of throw considering the pattern is so wide. You'd almost think you were dealing with multiple LEDs the way the spill seems to be very bright while still staying focused for a considerable distance. 5/5 for brightness The carrying case is very nice, & comes with a quality 21700 battery (not proprietary) & extra seal. Clip on side is also quality. So 5/5 for all that as well. Functionality is great, you can turn it on/off, by both the tail switch, the tactical switch or the side switch, 3x options with different shortcuts. Plus your strobe & sos of course. Can be charged with battery inside the light, nice occasionally when your packing or etc & don't have a battery charger station. Has the button AND tail switch lock out, no worries accidently turning it on in your pack! As far as functionality goes, I can't think of anything else you could possibly want in a tactical light, it's a solid 5/5 on functionality. Quality is great, seals are good, nice design, hard not to love this light! For comparison, I put it up against my FENIX TK22UE Which is an amazing 1600 lumen EDC "thrower", & originally I planned to send one of them back, depending on which one I liked better. Well long story short, I can't part with either one! I consider my FENIX my indispensable EDC, but the KLARUS was so good, I had to keep it too! This would also easily compete with the new OLIGHT M2R Warrior pro, & is much better I think because you are NOT committed to using olights BS proprietary battery & charging system. They are just slightly different animals.... Both use the same CREE LED, cost about the same & are constructed similarly with the same warranty. So if you're looking for a "thrower" for distance, with more minimal spill, you might like the FENIX TK22UE better, but if you like more functionality & incredible layered spill with a nice Beam that just lights up EVERYTHING in your path in all directions, you absolutely can't go wrong with this KLARUS, It's amazing & is incredibly bright all around, the beam, the spill, & the outter layer, everything. Hard to believe it's just one LED. They did a great job with this light, that's why it's now my go to light for woods, caves, anything like that where you need to see more than just a small "Hotspot" in the distance. The only thing I wish they had included is a 18650 cap for this, so I could run those batteries when needed without purchasing it separate but that's getting pretty picky, you can pick those up for a few bucks. 5/5 all day long