Not really convince at the beginning as the whole set of Thomann zen together provide a really dark scale. Sustain is long and get better after a short period of use, much better than on some Peter Hess i use to play. Good harmonic on 1.7kg and 2.3kg from beginning, it get quite ok on 1.2kg and 900gr. I have to try 1.4kg when available. 1050gr sounded dull and same note as 1.7kg so useless in the set.
In a sound bath, Thomann zen is more difficult to use than the peter Hess I use to have (scaled so you can play nearly random in tune).
Because of dark tonality/dissonance of scale first; building phrases becomes more demanding. and I will have to stop the sustain to control what would comes out of the mix, too much harmonics can turn to a stew.
...so overall it s really good for the price. And has a good potential.
As single bowls or for therapy it s great value.
As sound bath toys I expect most people if not musician would got lost
-----
Update after a couple of week and purchasing a Peter Hess set phk40 , the PH is much brighter and every stroke cut out of the mix easy. Problem with zen like in some conventional music instrument is ...I feel like spending effort trying to figure out the sound and define tone instead of flowing and playing. So..Zen are massively on the way back home/return. Not bad this say and not expensive.