Introducing my latest creation: a Juggernaut Sci-Fi Suit. I created this character because I love science fiction. I used Zbrush, Maya, Substance 3D Painter, Adobe Photoshop and Marmoset Toolbag. I hope you like it! See more details: https://www.artstation.com/artwork/g0Lo0L
If you are new to Zbrush, and want something for free, there is Meats Meier's intro to Zbrush 3, on his channel, on Vimeo. Although Zbrush has changed a lot, this still is a good introduction point.
No:) Use whatever topo tool you are comfortable with. If it is organic I usually use Zbrush but if it mechanical I will use 3dsmax. Try using Zbrush - Zbrush UV Master for Unwrapping...amazing