I’m a bit of a bell collector and bought my first singing bowl a few years ago because I was so impressed with the clarity of its tone (perfectly flat, no beats when struck). I think, like any musical instrument, one chooses best based on what is pleasing to oneself. Play them, whack them, hold them – a lot of them. The materials, shapes, manufacture, all vary widely and, consequently, result in widely different sounds. As they tend to be expensive, it’s worth your while to spend some time figuring out what you like, before you lay down cash.
Two technical points: First, for a lot of folks, playing them – making them “sing” – takes some practice. If you don’t already have the hand for it, spend a little time learning; I have friends and family who simply can’t seem to get the knack, so you might want to make sure you can do that, again, before laying out cash.
Second, if you plan to record it, be sure to do so with at least two channels. The bowls’ nodes move with the playing stick, so part of the magic of their sound is from your ears hearing the interference between the two vibrating fundaments; a mono recording won’t pick that up. Sounds flat and uninteresting as hell with a single mic.
Keep us posted on what you do!