We use "Image for Windows" by Terabyte Unlimited.
Here is the documentation for it: https://www.terabyteunlimited.com/downloads/ifw_en_manual.pdf
ImageW is a sector-based imaging tool, meaning it is not file-by-file. So it will exactly duplicate the disk.
Some useful comments made by user "Zman" in another thread:
ImageW is a sector based imaging tool from terabyte unlimited and is rebranded by LANDesk for use. Here is a link to the tool:http://www.terabyteunlimited.com/image-for-windows.htm .
ImageX is a non-destructive imaging tool from Microsoft. http://technet.microsoft.com/en-us/library/cc722145%28WS.10%29.aspx
What you choose is dependant on your needs. Not a rule but most people who deploy Windows 7 try and use ImageX. In my non-scientific benchamarks ImageX produced a much larger image and was slower than ImageW. However, ImageX is non sector based and non-destructive.
Sort of a Microsoft slant but anywho...http://windowsteamblog.com/windows/b/springboard/archive/2010/08/12/improving-your-image-sector-based-file-based-and-sysprep-what-makes-the-most-sense-part-2-the-pros-and-cons.aspx
Great info, thank you very much!