Greetings all - thank you for your responses!
I now have a Beaglebone AI, and I'm just getting into using the GPIO pins.
I understand about the PRUs, but for my application (motor control/power electronics), it would be really nice to have floating point operations available, which is why I'm looking at the on-board DSPs (if the PRUs are good, then the Cortex M4s are better, and the DSPs would be awesome...).
Now, I'm reading through the examples to figure out how to use the high performance DSPs with rudimentary tasks such as reading GPIO pins and triggering interrupts (I.E. a PWM timer that triggers a task every 10 usec).