I’m surprised people still read my introduction of the ES-87, but then again I’ve rarely been on GH lately.
Since considering something to be "quality" can be subjective and varies from person to person, I would say quality to me is something that withstands time and constant use, not just weight and heft of a keyboard which I've seen various people imply that just because the board is heavy, it "must be" quality. The brief overview I did of the KUL and providing shots of the internals was to show those who are fairly versed to see the PCB and the quality of the solder work. It was pretty clean with some spots of flux residue. Great soldering work and a well-made PCB can often attest to withstanding heavy use and time. An important aspect of a great case is how well the top fascia and bottom portion come together. I found that Filcos do that well, only to be trumped by the Leopold FC700R and 660M (quite possibly the 660C as well, but I haven't had the pleasure of touching one). How well a case’s parts are joined, combining the top and bottom of the case in conjunction to how well the plate is positioned internally aid with making an overall rigid keyboard. Since keyboard cases are generally ABS, how does one really determine if they're cheap? Does texture equate to quality? I know some plastic cases are thinner than others, and that makes sense to consider them cheap. But for some boards, their cases are thick enough to withstand being dropped.
With that said, the KUL is on par with Filco in terms of build quality. To compare both: the Filco with an average price of $150 from Amazon (more if directly from keyboardco) versus the $130 KUL from EK or MK, between those 2, I'd go for the KUL over the Filco for ease of availability and savings of $20. The texture and overall feel of the stock key caps from both are far better than what you would find on a KeyCool or QFR. KUL and Filcos are put together really well. Areas where the case comes together are flush where they should be. The plastic used for the KUL and Filco are thick enough that not only do they provide some rigidity, but keep the internals safe from accidents. I consider Duckies to be mid-tier in terms of build probably due to my bias of Duckies being somewhat of a novelty keyboard. Their primary focus seems to be more on programming their LED light shows than anything. I place Ducky to be within the same realm as the QFR. For those with a budget, looking to get the best-bang-for-the-buck AND is only interested in the usual 4 switches, I'd go for a QFR (especially when they're on sale) over a KUL. If you want something with MX clears, I'd choose a KUL over the WASD Code.
Quick background for me as well. I've owned 3 Filcos (an MJ1 and 2x MJ2s), a Leopold FC200R, FC700R, FC660M, Ducky Shine II YotD, Ducky 9008 G2 Pro, KeyCool 87, taken apart and tinkered with 2 QFRs, a Ducky Zero 9087S and played with a WASD Code briefly (and that’s not counting the 60% boards I own or have modded).
