The Volcano Tube Tank was the worst for me. The priming process is a nightmare, its too dry or flooded. Really picky about juices too, but the really bad thing is how the tank slides over the coil unit. Im bad about picking it up by the tank so it slides right off and juice gos everywhere! I had the 3.5ml one so im sure you can all imagine the mess.... Dark times they where. I liked Vivi novas but i enjoy cinnamon juices alot and they proved too eat right through the tank, more mess for me. Ive had a pro tank 3 now for about a month and im impressed so far with it, no issues too report on that. I have been interested in the drip style setups where you build coils ect. for a while but lack of knowledge has kept me from getting one so far. I hope being on here will help me with that within the next few weeks.