I have used a few and shot them into dead buffalo and elephant. Penetration was shocking, if they hit bone, they bent and tumble. I also had trouble loading them withoout damaging the necks of my .450 Rigby's cases.
I have not tried them on PG, but have heard reports of friends who did, and where happy. They look too odd for me to ever like...!
BTW, 500grains, i really like the little video at the bottom of your posts!