I was pleased to see in my local store the new Quantum 3700 lumen flashlight (item #57292). Previously I had wondered why the 1500 lumen light (56652) was on clearance, and, while the two lights don't really overlap in terms of capabilities or intended use, this new one has at least one major improvement that makes it more functional in terms of it being a police or security light. That's not to say that it is without fault, but I am happy to see Harbor Freight actually making an improvement in their products.
The biggest gripe I had with the 1500 lumen light was its switch. I am a firm believer in the doctrine of light discipline that basically requires momentary activation of a flashlight, it's what I was taught at the and the vast majority of Quantum light—and all cheap flashlights, really—have what's called a "reverse clicky" switch. That is to say the user has to fully press and release the switch before the light will turn on. A "forward clicky" switch will turn on the light with only a half press, and the light will turn off when the half press is released. A full press will keep the light on continuously. This new flashlight, I'm happy to see, is a forward clicky!
Unfortunately, that's where the improvements end. Let's start with the switch. While the forward clicky activation is definitely better, the multi-mode switching circuitry is still disappointing. The first activation turns on the full power. The second activation turns on the "low" mode (keep in mind it's still a very bright 800 lumens). That's not terrible or even unheard of among police lights, but it's still suboptimal. Unfortunately, HF has thrown a third, useless mode in this light and then forgotten to mention it! The third mode is an SOS flasher. Yes, it flashes Morse Code SOS. A strobe would have been unwelcome as a third mode, but even that would have been better than SOS. Worse yet, modes cannot be skipped. Your first press will always get a high beam, the next low, the next SOS, and then it repeats the cycle. I'm also not a fan of the placement of the switch on the tailcap. For a light that is almost a foot long with a huge focusing assembly on the front, the tail switch will be uncomfortable to use after a while. A body-mounted switch would have been a better choice here. The tail cap itself is also large in diameter. I didn't bring any of my flashlight rings, but I wonder if it would even fit in a D-cell ring.
The body seems to be of the usual good quality with no defects in the machining or finishing. The fact that it runs off 12 AA batteries is a bit odd. The extra voltage must be what powers the high output, but I don't know if fewer, larger batteries would give extra runtime.
The head of the flashlight is another concern. I am not a fan of the "zoom"style flashlights. It's a gimmick, it's detrimental to performance, and it could be a weak point both structurally and for water resistance. That said, a twist zoom would be better than the slide zoom of the 1500 lumen light. This feature must be cheaper to make than a reflector like the one on the 534 lumen light, because I don't know why else they'd include it. I only used the light in the store, so I couldn't get a full appreciation of the light, but the output ratings seem believable, especially the 800 lumen setting. I use a Streamlight DS HL LED at work, and it runs about 700 lumens. The HF light seemed pretty close in the brightly lit store.
So, while I would not recommend this light to any police or security personnel, I will say it's an improvement over the 1500 lumen light for reasons other than the output. Do not buy it for $40. Use a coupon if you are going to get it, or wait for it to go on clearance for $39.97 when HF decides to change it out for a better design.