I have gotten redbull with 36 mg nic and 60mg caffeine. TH still smooth, but I'm starting to like that about their juice. I do feel i absorb at least some caffeine, and I saw on the news a story about an inhalable caffeine they are selling online somewhere. i have used a caffeine spray that you spray under your tongue and absorb that way so I'm pretty sure I get something through the vaping.
I like the redbull, cherry vanilla, and bananas foster. CV and BF benefit from steeping. My last order i got triple shot and it smells a little like burnt sugar so I suggest double shots or single. Steeping seems to be helping the burnt sugar aspect.
Also got white chocolate cappuccino, its the only dark juice i have used from them. Taste is good, also a triple, probably should be a double because it is a little heavy on the black coffee taste.
Oh, I used three of their flavors in a tank and they turned black within a couple hours, so i would not suggest them for tanks, at least not the flavors i mentioned.
I love their price and like their flavors, but triple shot can wreck it, had good success with double and single, i would start at single and see if its not strong enough for you.