To be honest it's a mediocre light with nice badging around it.
i have kessils (a360x), twinstars, fluvals, and ai primes to compare across various tanks, and i'll be damned if anything approaches the attractive presentation of kessil light. they are damned expensive, but they're also well-built, quiet (i'm looking at you, ai prime) and grow plants well.
what makes them great - that tiny, high-density diode patch - also makes them much more difficult to implement well vs. say a panel light like a twinstar. first and foremost, you pretty much have to have at least two of the damned things because while power and (to a lesser extent) coverage could be adequate for a given tank with one, it's far too easy to get shadowing, wilting, and ultimately, algae. anything that gives equivalent presentation (or the aspect of it that i like) would also require small diode patches and would suffer from these same difficulties.
now, in terms of spectrum... i'm not comparing histograms, but it grows plants well, it's tweakable and looks great with some fiddling. as to that fiddling... apropos to this thread, i don't like the look of the kessil light until i mix a good amount of red into it. thankfully the newer models have independent red and amber channels (i only really use the amber for sunrise/sunset).
these other lights you note may be great and even a good bargain, but that doesn't mean kessils aren't great at least for certain people in the right circumstances.