I just got back from a trip to Germany, connecting through the UK. I had three 30 ML bottles in my baggie, along with my travel contact solution and two small 3 ML dropper bottles full of e-liquid. Not a single security agent in any country batted an eye at them.
Regarding all other equipment, I took my Pure Smoker Prodigy V3 and Icon, four 14500 batteries, six RCR123a LiFePO4 batteries, chargers for each type of battery, about 10 cartomizers, and 5 atomizers. All of this was in my carry on.
The only time an agent asked about any of my vaping gear was the airport in Munich on the way home. I had put my Icon (fully assembled with battery) in the front pocket of my backpack. He asked if he could look in my backpack when it came through the scanner. Of course, I said sure. He pulled out my Icon and looked puzzed. I said it was an electronic cigarette. He said "how does it work?". I showed him the button and took the battery out to show him. He said OK and put it back in my backpack. Oh, and he also fondled the 8 tins of Swedish Snus I had in there as well. But he didn't comment on it.
So no one in the Atlanta airport or Heathrow (London) even batted an eye when I was going and coming back.