I cant find anything I dislike about the subtank mini, and I am very particular about anything I would say that about.
I guess the only downside is that it goes through juice faster than other tanks, and any dripper I've used. But with the airflow how could it not. Lol
I believe the air flow is only part of it... the coils are built at about 3mm with enough cotton to fill them... I haven't put mine down since I got them.
Between the various Subtank models, The Atlantis and Delta II... the minor differences between them in flavor and vapor production doesn't really favor one much over the other. I've tried the Smok VCT ( Vapor Chaser Tank ) as well and compared it to the Subtanks... in my book the Subtanks still have better taste but that may also be juice dependent since I only did that comparison using one flavor.
The Subtanks make the most sense in terms of power consumption to get that flavor/vapor so on a regulated mod, your batteries are going to last longer. The Subtanks seem best between the 25w-30w range depending on the person... I vape my own at 23w typically at this point.
On a Mech Mod, things change and suddenly with a Subtank you are overpowered and outside of their recommended settings. This is where the Atlantis that seems to be liked by most around 30w-35w or there abouts. If someone is wanting an even cooler vape on a mech... the Delta II may be good since it seems most people are recommending in the 40w-45w range for them. The VCT is between those, I preferred it most at about 35w and since I tend to vape cooler than what seems to be average... I'd place it to be best in the 35w-40w range.. it hasn't been out long enough for me to average what others are finding as their sweet spot, so its a WAG of mine at best.