For my taste buds and others I've had try it, it has a burnt oniony taste that we hate. I think cooking with something could help dull it down, haven't ever tried yet, since rather just eat things in allium family. But I hope to get used to the taste or learn to prepare it so I can consume it for its health benefits that it suppose to have.
Here is a link that you may like if you have never read it, was topic about this plant and some people do indeed love the taste, maybe a cultural thing.
Toona Sinensis topic
Regarding flavor: I've found and watched a number of videos showing people cooking with Toona sinensis in various Asian countries. The common thread that all the "in the know" people tend to employ is that they all blanch the leaves in boiling water briefly before continuing on with the food prep. I suspect this is a standard preparation step for a reason. It's challenging to adopt new plants if we don't also have access to the connected cultural knowledge for how to use them.
Happily living in the valley of the dried frogs with a few tiny ads.