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
Thank you very much. What is meant by non-destructive and destrutive. I know the dictionary meaning but how do you mean it as it relates to imaging
ImageW is a sector based tool so when you restore an image it will effectively erase everything on the drive. ImageX is filebased so you can restore an wim image without erasing the drive - readers digest version of the explanation.