Howdy Bryan,
No experience with Mary's Cherry rub, but I do like Head Country rub and sauces. The rub is pretty salty and not hot, so I usually amend it some. I have been experimenting with a mixture of 1 part Head Country, 1 part Wild Willy's, and 1 part Old Bay. Still experimenting.
As with most things, it's "good" if you like it. Give it a try and see what you think.
George