Ive been vaping my Kanger Aerotank Mega on T3S coils for weeks now. The stock dual coils are low life products. The T3S has had its problems too, but not as bad as the dual coil heads. The T3S screws right in a vapes like a million dollars. My problem has been with Nautilus, Aerotank Mega, and generally all the Kanger heads I've bought lately. The QC problem is in the silver solder joints where the non resistive legs are soldered on to the coil itself. These are breaking down and rising in resistance as you vape, then finally opening up when the joint fails and the leg is no longer attached to the coil.
I'm not a high voltage vaper. I vape a 2 ohm coil at 3.4v until the new wears off. Then, I crank it up about .2v at a time until I can't hack the flavor anymore or it goes open on me. The 2 ohm T3S coil I installed this afternoon was great for a few hours. It's almost midnight and it's up to 3.1 ohms and getting weaker by the minute.