Ah, lavender. Lavandula angustifolia, as it were. My favorite herb in terms of aroma, and appropriately, it is commonly used in aromatherapy.
Equal to its scent, it makes for a pleasant herbal tea. A gentle and flowery taste with no bitterness, almost like drinking perfume if it tasted as good as it smelled. I don't have a lot else to say about it, other than that, like chamomile, it works well in mixtures.
When it comes to medicinal applications, scientific literature almost exclusively discusses aromatherapy or topical use, though, anecdotally, I am certain there's something else, less explored, about the chemistry of lavender. I have experienced a relatively mild, but still quite noticeable sedation and anxiolysis from lavender when drank as a tea.
In one experience, I drank several cups over the course of a day, with the effects gradually increasing in proportion. I would describe it as a profound calmness, culminating in an ethereal feeling, like levitation, or floating effortlessly, as one would in salt water. The excess did cause a headache in the end, however.
It can also be smoked, vaporized, or smudged, but I have not personally tried this.
My grandpa uses lavender oil when he irons our clothes. Very nice.
Summary: 8/10. Good taste. Sublime aroma. Simple as that.