It seems to me like ZBrush is more professional than Mudbox. Here’s some up’s and down’s of them: •ZB seems like it has a better userbase (meaning more tuts, more communities, etc.) •ZB’s interface takes a while to get used to •Mudbox doesn’t work for Macs. •I think Mudbox uses more RAM than ZBrush, but I’m not sure. •The prices: MB: $650 ZB: $490 •Here are the system requirements for Mudbox: Microsoft® Windows® XP 800 MHz Intel® Pentium® III processor (or equivalent) and later ethernet adapter 512 MB RAM (2 GB recommended) 1024 x 768, 16-bit display (32-bit recommended) 650 MB available disk space (2 GB recommended) recent OpenGL®-enabled graphics card (Nvidia GeForce graphics cards recommended) Wacom tablet (recommended) Notes: Mudbox has not yet been fully tested on Microsoft® Windows® XP x64 or Vista. IMPORTANT: Latest graphics card drivers are required for proper display. Latest Wacom drivers are required for best tablet support. When installing a new Wacom driver, be sure to first uninstall the old driver, reboot, and then install the new one, as per Wacom's instructions. Failure to do so may impact performance of the hardware. Mudbox has not been fully tested with Wacom Cintiq. •And here are the requirements for ZB: PC Recommended OS: Windows XP CPU: Fast P4 or newer (or equivalent such as AMD) with optional multithreading or hyperthreading capabilities RAM: 1024MB (2048MB for working with multi-million-poly meshes) Monitor: 1280x1024 monitor resolution (32 bits) Minimum System Requirements OS: Windows 2000 CPU: PIII RAM: 512MB (1024 MB recommended)** Monitor: 1024x768 monitor resolution (32 bits) Mac Recommended OS: OSX 10.0 or newer with either BootCamp (using Windows XP or Vista (32-bit) or Parallels (using Windows XP or Vista (32-bit) CPU: Mac Intel RAM: 1024MB (2048MB recommended for working with multi-million-polys and when using Parallels)** Monitor: 1024x768 monitor resolution set to Millions of Colors •Here is a pic of the Mudbox interface: •And the ZB interface: NOTE: Those pics might be old, and the UI might have changed a little. I hope that this helps you.