Man... I love your work! You're extremely talented!
Quick question if I may... Have you ever used Autodesk Maya? It's what we're taught to use at the Uni I study at but when I see work done on ZBrush I'm always blown away. I'm just asking to see which is preferable to use in terms of ease to use when sculpting, texturing, rigging, etc and what you can achieve with each program. I tried using ZBrush once but got completely lost in its interface.
Thanks a lot!! No I haven't use it before... I'm not a experienced 3d artist, zbrush is the only app i know, in my opinion you have to choose both, each one has his own field and can be complementaries, and both are very used on the industry Zbrush has a strange interface because is very singular, i recomend you to check out the getting starting guide ([link])it is very useful) and if you need some help don't hesitate to ask me