I got a room on the Club floor when I was there last month. The Diamond Amenity was the same nice box of 9 truffles/chocolates that they sell in the lobby for like $13. The last few times I was there (although this was 2-3 years ago) I got a free drink in the Lobby Bar as a Diamond Amenity.
One interesting thing is that in my room there was a door hanger for a "free room service Diamond continental breakfast". I assume it is given to all Diamonds, although I'm not sure why they would give you room service breakfast if you are already on the Club floor. Although I'm not complaining. I ordered the room service breakfast and then I went and got my fill again in the Lounge.........................
This was my 5th time there and this time I
FINALLY made it across the street and to the top of the tallest building in the world (Taipei 101).