awesome work. you are a talented artist!
sculptris is a very feature limited version of Zbrush. It is a voxel modeller/sculpting tool which gets you familiar with some ideas behind that.
Zbrush is on top , It have an edge specifically in sculpting high-res geometry. the brush engine is just the best out there in terms of customization, control, and feel.
I've used XP-Pen Deco 01 V2 drawing pad in Zbrush for years, fantastic for drawing. I've gotten accustomed to it and the ergonomics point is big.