I think the best way is to settle this in your mind is to conduct a scientific experiment: build a compressor with both cheapo tayda components, and one with high-end parts, then have a blind sound test.
I'd certainly be interested in hearing the results.
I appreciate the impulse, but I gotta point out cause I'm a stickler and not particularly neurotypical myself...
This is not a scientific experiment. The same test, conducted multiple times by different individuals attempting to account for all variables while using a shared vocabulary to document results in as close to objectively as is humanly possible: well, that would be SCIENCE!!!!!!
But...if one is interested in what difference is noticeable to an individual on a specific day in a specific environment (including at a specific temperature)...honestly that gives me an idea...
So...MLCCs are something that I've been curious about for a while here. From my understanding, C0G/NP0s appear, on paper, to perform similarly to polypropylene film capacitors, so I don't have *any* qualms about using those in the signal path.
But...let's say...if one was to use a Z5U MLCC. Those have a horrific temperature coefficient.
So...even if one was to measure capacitance outside of the circuit, the actual capacitance in operation could shift to, like, half...say, if one was to leave a pedal out in the sun on a stage during a hot day...
Even an X7R can shift to a lesser extent in different temperatures. Not a big deal for something like power supply decoupling, where the absolute value isn't super important, but enough that I can't help but wonder if differing environmental conditions could, say, shift the effective frequency range of the tone controls on a drive pedal in an unexpected and unwelcome way.
Too many unknown variables for me to say with certainty: I think it's fair to say that resistors do not particularly matter as long as they arent carbon comps. Caps are complicated though: for pedal building, I don't think you can go wrong with C0G in the 1000nf and below range, Polypropylene below the 10nf-ish range, Polyester in the 10-1000 nanofarad range, and electrolytic from there on up. Just in terms of ease of cramming everything in there.