I
you don't need to dump your juice when rebuilding on the subtank mini....Cubis is like a cup with juice, subtank like a cup with holes in the bottom.
Cubis you can remove your coil/build without having to dump the juice first, goodluck trying that with the subtank.
The one great feature of the Bellus is turning it upside down with juice still inside, removing the build to rewick or recoil, very handy.
The Cubis goes one better in that you dont have to turn it upside down first.
Cubis + RBA option = Kentucky Fried dinner... IMO.