jeffkazoo, Welcome to epicski by the way. You'll find a real diverse bunch of regulars here with a vast amount of knowledge to be had. Here goes. my Son's roommate in College skis both the Madtrix and the Mojo, mostly because he gets them for free. He is a world class skier who just missed the XGames last year but competed in the USFreeskiing open in Vail and a few other comps around Colorado and spent most of the summer in europe and Whistler skiing with the Pros and doing clinics. His take on Heads. If he didn't get them he'd buy em anyhow. He likes them. He's on the Madtrix most of time he spends in the park and on the Powder days he's on the Mojo. He's beat the crap out of both of them and the sidewalls amd metal edges are bulging but he still loves them. He's not a big mogul skier and i've never tried them in the bumps so I can't vouch for how they are in bumps but the width of the Mojo wouldn't help make it a bump ski. If you are set on the Head Madtrix for your park/bump ski then I would go that route.
One thing I'd like to add, I have skied the Mojo and it is a fun, do everything ski that is awesome in both powder and crud. I'd own one if the price was right.