If I handle them as soon as they arrive, I might as well just do everything in the ISR as Russell suggests, which may not be a bad idea.

I have a super loop in main() that just updates LEDs and debounces buttons, but my button debounce routine loops infinitely until a button is released, so dealing with the MIDI buffer there would not be ideal.

All other activities I was trying to keep interrupt based also. Sending MIDI bytes, which will be tempo based is ideal for a timer interrupt.

I googled for any MIDI examples, but almost everything was for sending bytes, not receiving them.

Thanks
John K.