This is just my attempt to run a basic list of the common black box led fixtures available as of this date.
The range of more inexpensive or economical "˜black box' fixtures runs from very basic $100 units to $350 units with lot of features (even better looking cases than the basic black box). The name "˜black box' refers to the fact that the case is just a rectangular box and not exactly aesthetically pleasing. That's OK inside a canopy, but some may not care for the look so much when it's just sitting on the tank. Most are either steel or aluminum (better) and painted or powder coated (better).
To be sure, I have missed or left out some brands here. This isn't an effort to review every brand, just to give some basic understanding of the features available and some basic costs. Two features I didn't cover are how many power cords each fixture uses, some have 1 and some have 2. Or the fact that basic fixtures have manual only controls, but those with more features may have remote controls, or wifi, or apps.
MarsAqua ($100): The case is the very definition of a black box. It is the least expensive and has the fewest features, 2 channels of leds, one blue & violet and the other all white with a couple of red and green tossed in. It has 2 manual dimmer knobs and no timers. As with all the true black box fixtures, it uses Bridgelux or Epistar leds. They work just fine and they cost less than Cree leds. Each channel also has a manual dimmer to control the intensity of the light. They also drive their leds at a 15% to 20% lower power level than all the others. So it doesn't produce as intense a light as the others do, but it's adequate for 24" deep tanks. It comes with a hanging kit but no legs or rear bracket mount. SB Reef Lights ($140) has a very similar version with legs and run at higher power levels equal to all the other brands other than MarsAqua.
Reef Breeders SuperLux and SB Reef Light ($200) are better fixtures that are almost the same but have built-in timers and digital dimmers with a remote control and both have adjustable legs. There are Viparspectra and Galaxyhydro brands (various sizes and prices) that are just like these Reef Breeders SuperLux fixture, but they don't have legs.
A better looking version of the 3 above is the OceanRevive T237B ($200). I own one of these. It's well made with an aluminum case, good fans and heat sinks. Like the RB SuperLux above, it has built-in timers and digital dimmers and adjustable legs. But instead of the standard black box case, it has a more modern looking case that is thinner and the upper surface is curved at the front and back edges so the top curves down to meet with the bottom surface. The spread of leds in this fixture is better as well.
If you like the idea of having a sunrise/sunset/moonlight controller and a standard black box case (with rounded corners), look at the Euphotica led ($265). Or the SB Reef Light version in a standard 30" long black box with legs ($400). They look to be very similar to the EverGrow made Reef Breeders Photon original design (not to be confused with the Photon V2 which is a much nicer fixture).
Probably the least expensive Chinese made fixture that comes in a much better looking case is the Reef Breeders Photon V2 ($340) and the EverGrow version (common outside the US). This is what I have over my display tanks now. It's only 1" thick, very streamline and modern looking and has adjustable legs. It also has lots of extra features that cost more, but the light for the tank is about the same (actually, a little better) than all the true black box fixtures as it uses 3 and 5 watt leds by Cree and OSRAM. It has the sunrise/sunset controller, but it also is the least expensive fixture to have 6 channels of led control (a channel for each color of led) that can ramp up & down separate from each other. This gives great control of the exact color in the aquarium, if that's important to you? Just to be clear, your corals are happy with lots of blue, half as much white and maybe a dash of red.