The biggest problem I have with interest check, and why I don't like them is I don't really know what the majority wants/needs. Always only end up with a small amount of VERY outspoken people with a particular opinion and I have no clue how valid that is in a broader sense.
And being a relative newbie, I don't want to offend you (or others) by speaking my mind, so I tend to keep quiet. But here's my perspective on this, from someone NOT outspoken.
I don't really like the colours, but I can understand why others do. It kind of comes across as a set that would be great to combine with keys from Miami, or with other GMK keycaps, cyan colour packs, original Cherry keycaps, etc. But for a newbie with no other sets yet, it's just a bit boring for my taste. Maybe if there were two keycap colours, not just legends, that might be more interesting. I mean, I like (and bought) GMK Hyperfuse, which has cyan and purple, so it's not that I don't like the colours, they're just not popping for me on the black.
The spanish legends: They add interest, but I'm not "wow" over it. I don't like the front printing in a different colour. It's not that it's different, it's that it's swapping with the two main colours, and the legend colour is no longer the delimiter between alphas and mods.
Numpad Enter: Eww.
Row Profiles: Bothers me. Probably not as much as JD, but still... it comes across as catering to the winkeyless crowd and ignoring people with modern stock keyboards. If GMK doesn't make 1.25U keys in R5 profile then deal with it in the most sensible fashion and use R4 profile for all bottom row keys. I just don't get the reasoning behind it... authenticity with vintage Cherry? matching row profile with vintage Cherry? Why is the R5 profile so special that the majority (let's face it, the majority of buyers will be winkey TKLs and 100%s) must have mismatched bottom row profiles? It's a bit condescending to say that people with modern ANSI keyboards don't care about mismatched row profiles. "Oh there's a break between right control and arrow cluster" is not an argument I agree with.
Likewise, why use R0 for the function keys, but not Print, Scroll Lock and Break? Why are they "Print" and "Break" instead of the standard legends?
Mismatching row profiles became a point of discussion (and argument?) in the Triumph Adler GB... and IMHO you can't say a set is "compatible" with modern ANSI layouts (ones with 1.25U mods) if the bottom row has mismatched profiles. Therefore, this set is as "compatible" with modern ANSI as it is with the 1800 layout, or the Lightsaver. There may be keys with the right size and legend to fit the keyboard, but if it doesn't match the profile of adjacent keys, so it's only partially "compatible".