JUCE uses the same underlying drivers as everyone else - i.e. CoreAudio on iOS and Oboe on Android.
Android is the only platform where you’ll run into latency problems, but there’s nothing that Superpowered can do which we don’t already do in JUCE (and which every other audio library also does now that Oboe is available). We’ve worked with the Android audio team at Google to make sure we’re using all the right APIs to get maximum performance.
IIRC Superpowered used to offer some kind of custom Android audio driver which required a jailbroken phone…? That’s really the only way to beat JUCE/Oboe’s performance, but isn’t exactly practical if you’re shipping an app to end-users.
If it’s important to you, check out some of the Google talks about this at ADC last year, as they explain it all in some detail.