I have to say the V1 VT Inbox. This mod has been my everyday carry for about 3 yrs now (I have another one still in the box as a backup), though the
rda changes every couple of months. I own about 20 other mods, 10 of them Squonkers and no matter what the Inbox is always with me.
For me it checks all the boxes - the 3 to 4 bottles I have broken in are just right and I have never had one fail (I am sitting on a lot of spares), Temp control on the DNA75 is just perfect, and the size is just right.
I am not even sure which RDA is on it in this pic (the pic is an old one as the leather doors are not that nice anymore), currently I have a Reload S on it and a Hussar 2.0 in the mail