I putt with a Magnet, i used to use a Challenger. Never really thrown an Aviar except back in the day. But I just thought that is what every one compared as far as putters went.
I have been known to be wrong before : )
The FLX ASS is way more overstable to me than my max weight champ sidewinders. Joes Flight Chart says they're similar other than a slight difference in distance potential. I've known some of the FLX plastic to more stable than Z....i.e FLX Drone vs. Z Drone.