We've done a handful of mantel mounts. I will never use the 540 or below again. 700 and up are decent. But I plan to try the Dynamic Mounting product on the next one.
I have a motorized future automation EAD at the shop waiting to go up with an 85" Sony. The price is not out of control surprisingly. I'll post my thoughts once I install it.
"When I eat, it is the food that is scared." - Ron Swanson