Robert,
You will NEVER EVER EVER please everyone. You have some cool products. Maybe this guy being a mechanical engineer is pissed off he didn't think of it first?
Either way, having critics keeps us on our toes and honest. So chalk it up to one of the few you will never please. Don't let them get you down.
Congrats on getting the first "full build" customer.
That volvo is going to be really cool when its all done.
Good luck!
