I am not a gong expert. Although I took part at a few sound massages where singing bowls and gongs had been used, this is my first encounter with gongs as a user, and I have no experience with other brands.
GONG
The single 30" sound track on the Thomann webpage does not disclose much on the richness of this gong. All that comes through is how powerful its sound is. It deserves more care to inform customers. I was really anxious when purchasing, since I was not able to visit Thomann's place to try several gongs myself. Fortunately, I was able to try elsewhere a few wind and tam-tam gongs between the 70--120 cm range, only the 90 cm missing. I thought that a 90 cm wind gong would be the appropriate compromise among the depth of the sound, portability and budget, and I trusted my luck to receive exactly the gong right for me. Now I feel that is what happened. I have been using it for two years now. I enjoy the soft bass tones when hitting gently, then the overwhelming vibrations that fills the room. It is very sensitive to light touches. I use very different mallets and they produce a vast range of sounds from sharp knocking to very soft, deep bass. Playing it is a never ending discovery of soundscapes. Its deepest pitch is not exactly at the center but around 10 o'clock below the perimeter of the inner disk.
The gong weighs 12.6 kg and is ~3.6 mm thick at the edge. As others have already noted, the rims of the holes for suspension had to be smoothed with a fine file to prevent rope abrasion (fine sandpaper would also do; it takes just a few seconds.
Looks gorgeous in sunlight as well as with candle or warm incandescent light. I would not paint the Chinese characters, but once there, an explanation of meaning and a hint on pronunciation would be a plus.
MALLET
Dimensions [mm]: Head diameter ~90, Height ~65; Total length ~495; Handle length ~420, diameter 27--29. Weighs 365 g.
The white fabric cover of the head makes a tough coarse sound when hitting the gong, especially when hit gently. I prefer a softer sound, so I covered the head with a softer fabric to overcome this problem. 1--2 layers of polar fleece (polyester) soften the sound significantly. I tightly wrapped the head with 300 mm diameter circles, fastening them on the handle with cotton strings. Temporary fastening is perfect with rubber rings for trials.
The raw hardwood handle is sturdy, with a good balance. It is roughly made and comfortably thick, thus the hand does not slip and has a stable grip when using; a huge advantage over many of its super-polished high-brow competitors.