I think we need to separate the issues. Ugly or beautiful are highly subjective and personal matters, while “poorly labelled” – even if still somewhat subjective – is something that can be clearly related to the functional realm and hence is much easier to discuss in terms of universal principles. Also, the first is mostly a matter of taste the second is a matter of usability.
So just to be clear, while I think that’s it’s great that people can do what they want style-wise, I do firmly believe that accessibility and usability should always be a strong concern.
Which opens up a wide topic, so thanks @mlogger for bringing this up… and let me use your last examples since you already posted all those pictures.
While I would personally never put a Snazzy FX module in my case because my eyes hurt from looking at it (but again, that’s my personal taste) the difference to the grayscale is mostly in the odd colour scheme, which makes reading text a bit hard, and could be even more of an issue with people who have colour blindness. There would probably have been other ways to do a panel in that style but with better readability, just by changing the colours. The Wogglebug is probably a better example. While it employs black on aluminium printing, which is great for readability, the labelling and signal flow lines do a great job at confusing you. I find that even after using for some time (my bandmate has one) you keep patching it wrong because the graphics are misleading and confusing. Again, I think MN could have done something in the same style but more functional to the understanding of what does what.
Last but not least the Mungo is probably just confusing because of the icons, though probably that’s something that will be annoying just at the beginning. Most labelling on panels is there for two reasons: you need it at the beginning, while you’re still learning how to use the thing, and then as a memory hook to remind you what does what. In the latter situation you already know what the module does and how it works, but maybe you can’t remember which one is the exact knob or button to make it happen.
When talking about usability of modules, the labelling is only the tip of the iceberg, so to get this discussion back to something that can be useful to @Simeon , two other fundamental aspects that need to be taken into account are:
- the actual layout of the controls. Are the controls and jacks put in a meaningful way on the panel? You should make sure that they either follow the signal flow and/or are grouped based on the functional blocks of the module. A common mistake here is to think circuit and not musician. What I mean is: you need to think from the perspective of the person who will play the module and not from the perspective of the circuit. What happens in the latter is of course very important, but most people will neither understand nor care about it. What really matters is the sound that comes out of it, and how you change that by interacting with the controls. So the layout does need to make sense in practical use. This of course also means that controls need to be accessible, that you shouldn’t accidentally bump into a knob when flipping a switch and that jacks should not be too much in the way (though that is a war we cannot win I’m afraid
)
- the other thing is fine tuning the ranges. You should make sure that there’s always something happening when you turn a knob, push a button or throw a switch, and the ranges should be tuned in a way so playing the module is interesting and feeling natural. Easier said than done, but having that as a focus when developing the circuit probably gets you already halfway there.
From this perspective the Mannequins modules are great, but the Furthrrr is also really well designed from a functional point of view. Maybe the colour scheme isn’t the most optimal (red on yellow might be hard to read in some situations), but apart from that the style doesn’t really get much in the way with the usability of the module… and actually a lot of work went into the typographic details… but maybe I’m the only one seeing that I admit it.
This said, sometimes it’s nice to be that 5 year old kid when sitting in front of the modular 
