Right now it has to be my subtank mini on top of the OG kbox. It leaks when the temp rises but the taste and clouds are enjoyable. I rebuild the occ factory heads and can push the ohms up or down to my preference at the time (.4 being the lowest due to the kbox low resistance cutoff). Plus I drill out the juice holes to ensure less dry hits, if any. I can push 40 watts for $50 bucks all in (of course this is hypothetical at this point since I've spent well over this) and a lot of research.
The reason I have chosen the OG Kbox over my recently acquired Suboxes, I haven't been able to properly break them in and test thoroughly. I like the airflow design on the newer subtank mini, though slightly less airflow, coming from both sides feels right. Also, the new vertical coils are the new hotness. These things rock IMO. I can't wait tear one apart.
The subox was well designed. Feels great in the hand. The buttons are small .... feel pretty good. Love the new battery compartment. Magnetic cover on and off. Easy. Lines are clean. QC was somewhat lacking on the mods I received as the micro USB port was well off center on the black and slightly off center in the white.
The design is obviously above and beyond the kbox. I still like the minimalist look though, and is probably another reason I still favor it. But the subox is slowly growing on me.