I have the clusterHAT as well. You gotta admit it is one of the cooler rpi devices out there. It's a Big Mac sized super computer, even if it isn't truly practical; it is way cheaper than any other super computer out there, so the pi's reputation as an educational platform is accentuated.

I'm looking forward to transplanting it onto a Pi4, since it is more likely able to run the types of simulations I run, and the separation of network stacks will make it really hum. So much cheaper (and forgiving) than renting cloud instances too early on.