How good is the Obsidian plinth of Technics SP10 ?


Recently I heard an SP10 MK2 playing music at a friend's place. It was mounted on the stock Obsidian plinth. It actually sounded very good. I wonder how good is the Obsidian plinth compared to:

1. Typical after market birch ply plinths ?

2. Custom designed plinth like the Panzerholz plinths made by Albert Porter ?

Any ideas ?
pani
As for replacing feels on the stock plinth. Anyone tried magnetiske ones?


I do not want extraneous magnetic forces to be found near the cartridge.
Chakster; what is the total weight. Cant remember..
Anyway ,there is different versions , one of the manage 10 kg each.