Does capacitor brand really make any difference?

[NickKUK]

I use this quite a bit:

Filter Design and Analysis

They've got all the different filters you're going to bump into.

 

[nortiks]

Not at all.
The tone control circuit / cable capacitance, in combination with the pickups's internal LCR characteristics, forms a resonant filter.
You may find this helpful http://buildyourguitar.com/resources/lemme/

+ a million^^^. Just shunting the pickup to ground with various values of resistance significantly changes this response. And this is why a few manufacturers make variable Z inputs for guitar centric A/D boxes, which is simply a pot going to ground. It totally works and I built a pedal for myself that incorporates this feature. So it only follows if we had a shunt to ground whose resistance was not fixed, but is instead frequency dependent, well, we all know how that ends...a frequency dependent filter. And from the ESR plots of the caps that provide that data, we can see that it is not linear.