Crown vs TFV4 has been followed up with a sequel: Crown II vs TFV8 (aka the Cloud Beast). While each tank emphasizes different things, these two are far and away the most popular mainstream sub-ohm tanks on the market right now!
The Crown 2 by Uwell features a revised coil design to allow more airflow and a smoother draw, in addition to adding more organic cotton wick to allow longer draws without drying out your wick. This new Crown also has an easily removable top fill cap that will twist completely on or off in one turn, meaning filling is faster and easier with less mess! In my opinion the best all-around sub tank on the market
On the other hand, the TFV8 from Smok is an absolute monstrosity of a fog machine (thus the nickname). Everything from the coils, to the air intakes, all the way down to the fill port is bigger and beefier for ease of use and performance. The tank carries over feature from its predecessors such as a the swing-open top-cap and a heavy duty stainless construction. It has a 6ml capacity and a 25mm overall diameter, plus a super wide bore delrin mouthpiece to eliminate heat transfer to your lips. If you're looking for absurd amounts of vapor, look no further!