I sell both, have shot and tuned both extensively and own an invasion.
They are both equally quiet.
Riser vibration is equally non existent in both.
Here's why I chose the invasion.
The riser design (Center pivot) lends itself to a much more stable hold at full draw and it is much harder to torque the bow sideways due to the invasion having a deflexed riser and the Z having a huge massively reflexed riser.
The grip on the invasion is, IMO, a much better design, It is thinner, has the proper angle for a low wrist hold, and is just generally easier to shoot accurately. I'm not sure why Mathews can not put a grip on their hunting bows that is similar to their target bows??????
The invasion is definitely faster.
The split yolk over drive binary cam system is incredibly tunable. It is honestly the easiest to tune bows I have had the pleasure of owning or shooting. The back wall on the invasion is much more solid than on the Z bow. The invasion is one of the very few bows on the market that you can tune to actually tune to shoot straight down the center of the riser.
The invasion actually balances slightly to the rear as it comes out of the box and when you add you accessories it balances darn near perfectly neutral. The Mathews is already very forward heavy and when you add accessories it becomes even more front heavy.
I don't know what the Mathews riser is made of (I assume still 6061 aluminum) but the Invasions riser is made from 7000 series aluminum and is much more rigid than 6061 and resists riser flex much much better.
The invasion uses a laminated limb instead of a solid glass composite limb.
I'll be honest here though. I almost chose a G5 prime centroid. This bow matches the invasion feature for feature and is one hell of a fantastic shooting bow. The only reason I went with the invasion over the centroid is because I like the grip a little better on the invasion.