My advice for people that aren't having luck with them right out of the box is to try different juices, heads, start at the lowest voltage and work your way up. Started with my favorite 70PG/30VG juice on a 2.4ohm head.......hated every voltage. Boiled the heads, ran through 1/2 dozen tanks with 2 different 2.4 ohm heads, cleaning every day, tweaking the wicks, caps, etc. Same thing. Poor flavor, poor wicking, poor vapor and dry hits.
Just pulled a second tank (bought two), put my second favorite 70pg/30vg in with a 1.8 ohm head. No boiling, cleaning, or tweaking. Best flavor I've had to date and can chain vape to my hearts content at 3.2v (5.7W).
Don't know yet if it's a bad run of 2.4ohm heads or maybe it just doesn't like key lime pie, but the moral is, they do work. Sometimes you just have to have some patience and play around with them.