[question] How big of a difference in performance is there between the RPi 3b vs 4b?

[theOtterWizard]

There's a few scenario's I'm specifically curious about:

1. If I'm just setting up a jambox system for use with jamulus for an individual and I already have a 3b I'm not using, is the difference in performance worth buying a 4b?
2. If I'm setting up a system for a whole choir to use as a rehearsal thing, should I save some money and get the 3b for everyone or should I get the 4b (plus the cooling case)?
3. Is RAM a bottleneck for jambox to an extent where it matters a lot which version of the 4b I get?

Any advice would be much appreciated!