Wormwood, or at least the one used in Absinthe, has a flowery, extremely bitter, almost metallic flavour to it.
The effects of smoking the extract (or a lot of plant matter) by itself, or even ingesting it as such, are hardly noticeable. It is a good idea to try it first with cannabis then try it alone, since you will know what to look for. Otherwise, it is extremely subtle by itself.
As for thujone, I would say that I think there is probably another chemical in wormwood that causes its effect, but not Thujone. I don't have a lot of info on it, but it could be Absinthin, the chemical responsible for its bitter taste, thatis psychoactive.