I drink Yerba Mate every day. I started drinking it every morning instead of my coffee to reduce calories and caffeine intake. It has about 1/3 the caffeine of a cup of coffee, but I don't need the sugar and cream with it. I don't know about vaping it...I am not opposed to it and might give it a try if an extract of it were readily available.
I've also tried an herbal remedy to stop smoking before I found out about ecigs. I still have the Lobelia and some other herb, can't remember what it was. I can only say that it didn't work for me, because I needed something that mimicked the action of smoking more than taking a pill. Ecigs work much better for me, but I am still looking for that missing ingredient. I'm down to 1 or 2 a day and holding steady at that for several months.