I vape the Harmony CBD liquids in 300mg and 100mg strengths - they're not cheap at about £25 and £49 respectively for 10ml. My main reason for use is anxiety and stress relief.
I think they're good. For the 300mg one I'd say that after 5-7 good pulls (12 watts or so), I'm ready to set the vape down, which isn't the case with nicotine. The 100mg is less "self limiting."
As I'm sure you know, CBD has no real discernible psychoactive effect, but after vaping a decent amount of it, I sleep like a baby and wake up feeling delightfully chilled, but not in that much of a hurry to get anything done!